Why do you think it's OK to shun Nazis, but not OK to shun Muslims? Both are opinions/belief systems, hence a choice, and both are, in their extreme versions, quite brutal.
If you legitimately can't tell the difference between a genocidal ideology and a religion then I cannot continue this conversation.
You could argue that Islam was foundationally rooted in violence. https://en.wikipedia.org/wiki/Early_Muslim_conquests
Also claims of being the "one true religion" no not inherently incite genocide, whereas Nazism does.