> other whatsapp groups that I'm not in, which are filled with hateful politics.
That brings the discussion from you to others users, and your goal seems to be to change how other users are affected by their time on a platform.
> The radical Bolsonaro whatsapp groups are a mix of top down and grass roots content.
You seem to be talking about motivated individuals who formed groups with a specific purpose and express their views and propositions in these specific groups (which you don’t belong to, as mentioned first)
Whatever way we slice it, short of the platform banning their related topics entirely, I don’t see how a neutral service could act about these people/ideas spreading, from a mere platform POV. You’re talking about thought policing private groups basically.