I mean I won’t because I’m not subject to British law.
Yeah, it is extremely unlikely, but if there are arrangements in your part of the world that provide for the reciprocal enforcement of judgments (as there are with other jurisdictions), still possible.
Social media sites can't sort their own sh*t out, nobody on lfcreds is going to get dragged to court. If it won't endanger the site or cause JD sh*t say what you want, be an adult.
It wouldn't mainly because the damages would be minimal. The more traction a rumour gets the greater the reputational damage the higher your bill is going to be.
Fairly good reasons for this of course. Some very well known news publications, who we can all think of, have set about destroying the reputations of innocent people by the use of innuendo and insinuation.