Kick the jerks. Ban them if they are repeat offenders. Provide mechanisms for people to shrink or expand how much information is shared and how easy it is to contact them.
I'm actually dismayed that to this day very, very few sites enforce a system where you must be recommended by someone in order to join, or by a friend to ask to be friends/communicate with someone.
Those that get perpetually harassed would be far less likely to have to deal with trolls if those trolls had to be a "friend of a friend". Is vouching so technically complicated we haven't done it yet?
There are social structures and conventions that haven't really seen much traction in software. Someone's totally out of control at a party? Kick them out and kick out the person that invited them too.
I know services like Slack are kinda helping this along a little bit - I'm a part of one or two Slack groups that I've been invited to by other people, with a bit of a pep-talk at the start of like "here's the sort of shit that WON'T fly here..." that are just small single-interest focussed groups that have kinda organically grown, but it's definitely a rare situation.
I think it's just education for new users (kids), and making sure they fully understand how the internet works and being mindful of what information they share where and with whom. Trolls (in all their levels of extremity) will always exist - anyone claiming they know how to "get rid" of them are fooling themselves
If people feel like they have tools to push back against trolls they'll use them. If they feel like they're powerless, they'll leave. If they leave the troll to user ratio skews a bit higher and might end up poisoning the entire community.
For younger kids today, a overwhelming majority of their lives are online, so it's so much harder to escape - both for work/education purposes and entertainment, so it's so much easier to keep up the waves of harrassment, so simply saying "just ignore it" doesn't really work these days.