You seemed to have ignored a software solution to the problem that allows individual users to decide for themselves. This has two parts, block and ignore. The actual diffence between the two varies with the implementation. Ignore means that all sign of the user who is ‘ignored’ disappears, as if they were not even on the site. None of their posts and such are visible, nor their profile.
Block covers another problem where they can actually reply to your comments on someone else’s post. You can choose both block and ignore. Peace and tranquility ensue. I found out about some trolls not long after I joined a site. It seems there were some 15 of them and I only knew a couple. So I laid a trap by putting up a post that accused trolls of all sorts of things. They talk to each other, in fact they even have their own sites, so they all ganged up on this post, actually 18. Thanks chaps and I promtly did the block & ignore — never saw sign of them again. It does work!