Antisemites aren't a disfavored minority, the Jews they're hating on are.
> How do you imagine the civil rights movement would have worked out if unfavorable positions of the time were suppressed?
Hating on a group of people for who they are isn't an unfavourable position that merits being protected. Or compared to a civil rights movement.
> Exposing them let's them be recognized for what they are
> What people really fear is that people will not be intelligent enough to discern these bad opinions, that is an entirely different issue.
How did that work, historically? It didn't, and still doesn't today - see Trump, Brexit, Orbán. It's not an entirely different issue, it's the same problem - not only is a group of people directly hurt by allowing those who abuse them keep doing so, but others might get impressed for whatever reason and join the hating group's ranks.
Are you saying that:
1. the majority of the population of <Western European Country X> are antisemites
or
2. antisemites aren't disfavored
because I would say that both of these are false. Few people are antisemites, and antisemites are strongly disfavored to the point of having their speech made illegal - and "punch a nazi" is a meme.
How do you imagine the civil rights movement would have worked out if unfavorable positions of the time were suppressed?
How would that work for LGBQ rights?
There is no value in suppressing bad views. Exposing them let's them be recognized for what they are. Suppressing them causes them to grow and fester in the shadows.
What people really fear is that people will not be intelligent enough to discern these bad opinions, that is an entirely different issue.