Assuming good faith, most developed countries have hate (and similar) speech laws, with Nazism being explicitly banned in most (all? maybe Spain/Portugal/Switzerland are exceptions) of Europe. Same goes for antisemitism, or in general racial/religious hatred/discrimination to various extents. It's not a slippery slope "oh what will they ban next", it's "this kind of thing has proven itself to be extremely dangerous and is detrimental to everyone, hence it's banned". And it has been for decades, and nobody has just added gay activists, including in very anti-LGBTQ countries like Poland.

You might also want to look up the paradox of tolerance, it's a fun read.