First off, from my perspective, it sounds like you are using your conclusion as your starting point. yeah, sure, I'll grant you the dutch probably agree with you, but that isn't an argument in favor of either of your being right.
Second, from your description it sounds like illegal speech laws are hate speech themselves.
"tools to opress" now I'll grant you the only people this oppresses are ****ty people, but that is the exact attitude that all oppressors have had in regard to those they oppress. A very large part of the point of Illegal speech is to keep certain ideologies and groups down and unable to express themselves, to "eliminate" those groups. When you make it illegal to say things how are you not "altering the political landscape trough a method other then discourse"? you are just flat out saying they aren't allowed to even make the argument. When is it never working to "eliminate dissenting voices"? For sake of brevity lets just call all that jazz "hate speech" can you give me a general definition of hate speech that doesn't include it's self? The very reason I oppose hate speech laws is because they are an example of the exact things you say they are trying to prevent. Hate speech laws are inherently oppressive, and that is why we find ourselves in the very position that started this thread.
and how do you know these people are wrong⸮ (rhetorical question) how do other people? how can you expect some edgy teenager to be able to defend themselves intellectually from very seductive bad ideas if they've never heard them before? if they've never heard the arguments against them? argue against hate speech, don't ban it.