EDIT: I know this is a wall of text, however you asked a string of good questions and their answers require context.

No.

Phew, I'll try to keep this brief because there's a lot of moving parts...

The first claims that Germans were holocausting Jews started in 1933 during Samuel Untermyer, Chair of the World Conference of Jews (i.e. Jewish leaders from every country) when he made his FAMOUS / infamous American radio broadcast (not even the most liberal historians or academics dispute this, they just never speak about it) declaration of a global Jewish holy war against German in July 1933. Look it up, it's on YouTube.

During that broadcast, Untermyer claimed Germans were crucifying and burning Jews at the stake. He neglected to mention how many Jews were being crucified and burned and nobody took his claims seriously. The Jewish controlled mainstream news of the world pretended to be shocked by the 1933 Jewish holocaust but everyone else thought it was fucking ridiculous which is why it was never mentioned again.

More importantly, Untermyer used his bullshit story to justify world-wide closure of all food imports into Germany. The World Conference of Jews were attempting to use starvation as a weapon in their holy war.

But why did Untermyer and the World Conference of Jews declare war on Germany?

I'm glad you asked: because the Jewish German Communist Party (KPD) coup of 1933 failed and Germany tried and sentenced everyone involved in the treasonous communist coup to serve time in prison. This enraged the World Conference of Jews who immediately called for a meeting in Amsterdam to decide what to do.

The World Conference of Jews decided to give Germany an ultimatum: surrender, fire Hitler and free every treasonous communist Jew and allow them to return to their government jobs at full pay... or the Jewish world will declare war on Germany.

Germany response was, "NEIN!"... hence the famous Untermyer radio broadcast that was made as soon as he returned to America from Amsterdam.

I hope you're still with me and I haven't forgotten your question, but wanted to set the correct historic context to answer it.

The Jewish holocaust claims didn't exist as anything but baseless Russian wartime propaganda / campfire stories until 1946 (a year after the end of WW2) and the Russian's claims were enjoyed by all but were taken as seriously as claims that Germans eat their babies.

The original Russian wartime propaganda claimed four million Jews were exterminated in the gas chamber showers at Auschwitz concentration camp, located in Poland.

This story was presented without evidence during the Nuremberg trials (1946) and assumed to be true, without question, by every judge.

The number was quickly increased to six million to also accommodate the gas chamber showers at Dachau concentration camp... and the story was feverishly printed in every Jewish owned mainstream newspaper in every first world nation and this time. Not as many people laughed as much as they did with Untermyer claims because they didn't understand that every Nuremberg confession was extracted using torture, including confessions to every crime that was later forensically debunked. This isn't disputed by anyone and even the Nuremberg judges acknowledged this during the trials.

The Polish government later officially revised the estimate for Auschwitz down from four million to 1.1 million after their investigation determined it would be scientifically impossible to execute more than 1.1 million Jews using Auschwitz's gas chambers and ovens.

Dozens of teams of scientists later forensically tested the walls, structure and soil from both the Auschwitz and Dachau gas chamber showers and found no residual traces of the deadly Zyklon B gas. Many tests were performed by different teams because nobody could believe the results, despite every team producing the same results proving NOBODY was gassed in the showers at either camp.

Dachau Concentration Camp Memorial Site staff posted signs in several languages to inform tourists that their "death camp gas chamber showers" were just normal showers.

And that's where the six million number originated.

To finally answer your question: NO: America didn't seriously believe Jews were being holocaust because the original pre-WW2 version of Untermyer holocaust story was a laughingstock and the "six million" number didn't "become a thing" until after the war ended.

Was hitler actually doing that?

Ten million German civilians and one million Jewish prisoners starved to death in 1947, two years after WWII ended, mostly because of allied sanctions.

This event is known as Eisenhower's Holocaust.

This event isn't refuted by even the most liberal historians or academics, they're just terrified to discuss it.

The Allies broke the German's communication encryption four years before the end of the war and during that time, there wasn't a single reference, mention, allusion, whisper or peep about holocausting anyone. Similarly, no Nazi documentation or photos were ever found within captured compounds to prove there was any plan or protocol to holocaust anyone, at any time, anywhere.

All we have is Jewish hearsay and starvation photographs.

We've all seen the photos of German prison guards burying starved prisoners in mass graves: these photos are the centerpiece of every Jewish Holocaust museum and History Channel documentary.

We don't know if these photos of starved prisoners were taken two years after WW2 ended, during the great starvation?

We don't know if this starvation was the result of allied forced blocking supply routes into Germany either.

Those photos do beg some interesting questions:

• Why were Nazi prison guards making the extraordinary effort to dig massive burial pits when they allegedly had massive crematorium infrastructure onsite?

• Why do some Jewish prisoners of the Auschwitz concentration camp remember relaxing summers playing soccer with the prison guards or relaxing by the pool and movie screenings, live theater productions and live music in the dining hall for their dining pleasure... whereas other Jewish prisoners from the same camp recall Jews being turned into bars of soap and lampshades and geysers of Jewish blood spraying from the courtyard grounds for no reason and magical dancing buckets of Jewish blood and being chased around by Nazi rail-car terminator robots? Who is lying (PM me if you want video of these interviews).

• Why are we officially taught that every Jewish prisoner was liberated by allied forces at the end of WWII in 1945 when we know that one million Jewish prisoners starved to death in 1947? We know those Jews weren't Prisoners of War and were mostly members of the Jewish German Communist Party (KPD) who were incarcerated after being found guilty of participating in their failed communist coup of 1933... so why lie about it?

• Why lie about it? Why are these one million Eisenhower's Holocaust Jews never mentioned by liberal academics, Hollywood, the History Channel or Wikipedia as part of the Jewish Holocaust when we're constantly reminded to never forget the "six million"? Why do so many liberals / Bolsheviks / academics / "experts" not consider those million Jews worth remembering? I think those poor Jews are worth remembering... so why try to hide it?

EDIT: I hope I've filled this with enough names and dates that everyone can research it easily. This is such a touchy subject that posting links to any site will invite censorship. If you want info on anything specific, PM me and I'll send you a link. Please be specific because it can take a lot of time to collate and reply to specific questions.