The Soviets were as bad as Nazis if not at times worse. And Putin is no more a Soviet (right now) than the ruling party of Germany are Nazis. Doesn't mean either are good, but that is not the correct label to use on either.

The only reason we don't demonize the Soviets and use that term as a derogatory one (although in my circles, both would be equally insulting) is:

1. Universities, the Legacy Media, and most government institutions are full of communists. As a result, they will not criticize the Soviets. Antifa are just communists using a double-speak name. If you ever watch their "peaceful protests", they use Soviet symbols. Because they are protected by the media and given a free pass.

2. The West temporarily allied with the Soviets to defeat the Germans so their propaganda gave them a free pass. In order not to make themselves look bad, they wouldn't promote the truth about them as not to make themselves look bad allying with someone as bad as their enemy.

3. At the start of the WWII, the Soviets and Germany had a peace treaty because it was convenient for both sides at the time. The Soviets only ended up fighting the Germans out of necessity. Some historians do speculate that the Soviets were planning to attack the Germans at some point, but the Germans were aware of that and attacked them as a first strike. Regardless, the Soviets cannot be defined as anti-Nazi because for a time, they were perfectly happy to ally themselves with them.

4. While the term Nazi does have a real meaning, in the west and even in the current war in Ukraine, it's being used as a propaganda term devoid of any real meaning. Anyone who is bad is a Nazi. This is the exact same tactic that Antifa uses. To them, anyone who is bad is a Nazi or Fascist, regardless of the fact that it is Antifa that employs all the Fascist tactics to gets its point across. In the countries that were actually in the thick of WWII fighting, no one referred to the German army or troops as Nazis. They were German troops regardless of what political party was running them. In fact, most of the German army were not Nazi party members, even if they took orders from that party.

Bonus facts: The first official fascist was Mussolini. He started out as a communist union leader. He even congratulated Vladimir Lenin on his successful revolution in Russia. Fascism is a modification of socialism/communism to involve patriotism as Mussolini noticed that while people are willing to fight and die for their country, they are not willing to die for "communism". When antifa says they are anti-fascist, they are not doing so because they fascism is so different from what they are, it's because it's actually very similar and they consider it competition. This dates back to the Weimar German Republic where there were 2 main factions fighting for power, the communists (where antifa comes from) and Nazis (national socialist). They only hated each other because they both wanted the same thing, control of Germany. Politically, the were quiet similar.