That question, fren, has a multi-part, layered answer which is....difficult, at best, to answer succinctly. You can't talk about one part of the Kalergi Plan or the Open Society Foundation without unpacking the entire satanic playbook because it's all interwoven into Globalism. See graphic: https://files.catbox.moe/b0a971.png

The "easy" answer is weak men, of which I am one, sad to say. Weak men and infiltration from within by a group of people ("shapeshifters" or name-stealers, if you will, that manipulate at-will by any and all means necessary). "Israel for last" - of all the drops Q made, I think that some of the most impactful ones are the ones in which he says the least. There is as much that Q didn't say, which he could have, but chose not to. "Disinformation is necessary" and the less spoken about certain subjects (like your question), the less ammunition the enemy has with which to use against us. Additionally, you start to fly too close to the sun and pickup the "conspiracy" label very quickly and now the movement gets derailed. I'm certain all of this was game theorized using Project Looking Glass.

Obviously, Q spoke about how they want us divided and fighting against each other - if you're busy fighting each other, it's classic misdirection tactic, but also preoccupied with fighting the wrong "enemy". But why has there been a (what I now would describe as biblical) war started against a specific group of people with a particular skin color. Satan wants everyone dead, but he very specifically wants this particular skin color to also be humiliated, marginalized, demoralized, debased and diluted.

Go back to WW2 and then WW1 and ask yourself how these these wars started and what happened as the result of them? General George Patton famously quoted that "We (America) fought the wrong enemy" and that the rise of the Soviet Union was the true threat to America. Brothers of Europe.....who were under Bolshevik control from the Red October revolution in 1917, while WW1 was raging. Conveniently, Patton ended up dead in a car accident in '46, as he was becoming more outspoken against the Soviet Union and saw the treatment of German POWs by Allied forces. The cause and effect of WW1 and 2 is one of the most heinous psychological operations to be perpetrated on America (and the rest of the world) and we haven't even gotten to the holocaust yet lmao. I believe very little of what happened in the history books, about any event, not just WW1/2 - Patton found out the truth too late. The rise of Nazi Germany served multiple purposes (not all covered here): 1) Let European brothers murder each other 2) ability to demonize future right-wing politics and the ability to shame/demoralize others by labeling them a nazi by those on the left. Very convenient, yes?

Circling back around to your question: I don't think it's as much as we "allowed" it to happen as we've been manipulated into giving up our freedom, over a period of many, many years. Paul Harvey's "If I were the devil" speech comes to mind here: https://www.youtube.com/watch?v=jnPE8u5ONls

This is all just an introduction to your question and I didn't do a great job of explaining because it's hard to talk about without calling a spade a spade and Q never covered these subjects, because it's hard material to cover for all of the reasons above and far more.