Facebook hate groups are real (anti-immigrant, anti-lgbt, ...). They're getting better at skirting the rules, so there's no way to disband them. I'm seeing dozens of such groups form for a country with a population of ~2 million (Slovenia). I think the mentality those bubbles breed is even more dangerous than Twitter harassment. Instead of manifesting itself in bullying and conflict, it's nurturing the different flavours of toxicity in nicely compartmentalised jars.

I can't agree with the author's statement, that design itself is not primarily responsible for a solution, as it is instrumental in enabling such an environment in the first place.