No misguided popular movement (or even factual information, lacking critical context of course) will be able to gain momentum, as its promoters will be unknowingly yelling into the void. On the other hand, movements and ideas that promote wellbeing and harmony will spread easily. It does not take advanced AI to categorize vocal people by politics, and quarantine those with hateful ideas.
This is our chance to safely defuse humanity's hateful instincts, and we should take it.
Best of all, it is completely ethical because, as a since-deleted post pointed out, it is vaguely hinted at in the Terms of Service. Voluntary agreements are the highest form of ethics. They are beyond moral question, and in fact the whole purpose of society is to enable and enforce them.
Those who don't like it are free to stop participating in online society. With such an easy and safe way out, there is absolutely nothing to worry about.