Acting is doing something, as opposed to saying something. One of them counts as freedom of speech and hint, it's the one you quickly attacked. It's when you go to work and do your job as per the contract which can demand you not express certain opinions in the office but not in your private life.
> I don’t understand quick defense of this.
You are like those people who gagged Kimmel because they didn't like what he was saying. You will quickly defend firing people just for saying they support abortion rights (which is illegal in many states), or LGBTQ+ rights. You playing the "you defend Nazis" card works both ways. Just like you taking away freedom of speech works both ways. I wonder if choosing a German name was intentionally ironic.
I don't have to like a guy or his opinions to defend a bigger principle.
The username is irrelevant and older than CloudFlare hiring Nazis
Today's Nazis have more diversified targets for discrimination. Concentrated antisemitism was a side effect of the personal issues of the most famous Nazi exponent in history, but they're more about racial supremacy. Today they might be Islamophobic more then antisemitic.
To answer to your question, their thoughts and views don't matter in the office, their behavior does. You can deeply dislike a colleague for various other reasons too but the effect is the same. I don't want to be fired because I unilaterally hate, or even love, my colleague. As long as I don't act on it, that is.
I know people working together in the same office where one's grandfather was in the Nazi military guarding one camp, the other's was a civilian killed in that camp. Whatever their deep feelings, they mind their job as expected.