It doesn't even hold up today because you are saying historically there were Germans that supported the Nazi party because of Hitler's leadership in other areas. But we're in 2017 where everyone knows that Nazis committed a genocide. So anyone like the Daily Stormer that supports Nazis we know to be dangerous. And It's okay to not do business with dangerous people who want to harm innocents.
To your point about Muslims, we know that there are millions of peaceful non-violent practicing Muslims. You are trying to make a logical equivalency here and what I believe is more important is the facts that we know about the real world we live in. Supporting Nazis is explicit support of genocide. Practicing Islam has an unfortunate overlap with violent terrorists. But practicing Christianity also has an unfortunate overlap with domestic terrorists like Timothy McVeigh and Dylan Roof. I don't think existing in this theoretical world of forced equivalency even benefits your argument as much as you believe it does.