If the crazy uncle is interested in socializing more, they can see how their social-media behavior influences that. If they lose followers, friends, or if it escalates to platform bans and restrictions, that can be data used to realize that that behavior is... anti-social. So if they're interested in socializing more, they change that anti-social behavior.
If they aren't interested in socializing more and just want to get their believes out there to as many people who are willing to listen, the social media platform absolutely does not have to tolerate that and should shut them right down. This will be evident by the loss of followers, friends, and eventual platform restrictions and ban. People that want to change will do so before the ban, and people that don't will get banned, and find some other community to try to be a part of; that glorious 5-person self-hosted Mastodon server nobody has heard of :p
Having a real-name attached to a public social media profile makes people think twice about associating themselves with less-than-mainstream views, publicly. Anti-social behavior isn't tolerated mainstream, and it's not hard to figure out what other kinds of communities fall under this.
I fully support employers scraping public social media platforms to determine if employees are a fit for their company. Don't like it? Don't work for em, or change your public views. Other people, platforms, and companies do not have to tolerate your views; you have that first-amendment right in the US to say your opinion, can choose to exercise it publicly, and thus choose to accept the repercussions that come with that.
Yeah it would suck if I was working at a company, said something not ideal on a social media platform, and got fired. Yeah I'd be upset. What's the problem? Most for-profit companies don't screen employees, train them, integrate them into their workforce, and then fire them for dumb reasons.
If someone has a scenario that doesn't match any of that, share it as I'd be more interested in a different view that doesn't come down to bigoted people being entitled.