Would you prefer a situation in which secret police agents tracked down troll internet users, and if they found those users to be Russia agents, they would shoot them? I might prefer that actually ;) but I'm not in charge of the secret police and so therefore its not in my capabilities to make that happen.
Of course, it is possible that this conspiracy theory is false. That Czechs, or a large portion of them, actually are that hateful (also likely). If that is the case, than this country is on the edge of a genocide (against Muslims and Gypsies) far more brutal than Nazi germany. And in that case, anonymity would be a good thing for all the activists who try to fight against the hate.
So you're right, that it is a very difficult question.
Maybe it's possible to just ignore the anonymous vs. non-anonymous question and target the speech itself: if it's hate speech, you kill it. If it's lies and misinformation masquerading as the truth, you kill it. If the poster has their real name attached to it, then you may have a legal means to ensure they stop posting things like that. If they don't, obviously it's harder, and you have to keep chasing after them as they create new anonymous accounts.
I'm not trying to hate on google. But everyone says that it is impossible to compete with google, because their product is perfect, that it would be impossible to make a better search engine. I don't think that's true. I think there is a lot of inovation that still can happen when it comes to sorting through the internet.
Beyond a point, the scale and complexity of the information goes beyond what is required for a simple conversation.
Most people want the information spoon fed to them. The issue is that they may not even be framing the correct question.
To correct that they will always need to (at some point) engage with complexity.
And as long as someone can meme or use cheap arguments to dodge a difficult/complex point, theres no real advantage to that level of complexity.
So the only people who are digging that deep are people who want to figure something out. For them, google works just fine.