For sure, it would be foolish to assume that the problems could be solved by changing the software, or passing a new law. Policing private groups is impossible. We're living in a new world of social media and we still need to figure out how to deal with that. I hope that in the long term there is some kind of culture shift with how people interact with the internet, because whatever we're doing today isn't working.
By the way, I mentioned Bolsonaro explicitly because those groups are currently the better organized ones in the Brazilian social media space, masters at exploiting the Whatsapp dynamics. But the fundamental problem is not exclusive to the extreme right.