I'd state that differently. The law is the limit on how bad you can act and get away with it. Wikipedia shouldn't be smearing people because it's an evil thing to do, not because its a potential tort.
This is particularly important because not libeling someone is not sufficient to prevent them from suing you anyways in any case. :) ... and focus on legal limits results in outcomes like telling people reporting serious crimes that you don't care because you're not obligated to under S230.
In any case compared to practically every other large internet site Wikipedia does a much better job behaving ethically. I've wasted weeks trying to get reddit to take down posts of hacked nudes on a subreddit specifically about posting hacked nudes and sending them to the victim's coworkers. Google does nothing about scam videos/adds reported to them, etc. With english wikipedia, you can hop into a chat channel or mailing list and reliably something which is obviously wildly inappropriate will be immediately handled. 95% of this is because whatever their flaws the site is operated by human beings that care about doing the right thing, rather than some accountability free corporate human-centipede. The remaining 5% is because Wikipedia Is An Encyclopedia, and so some of the free expression tradeoffs that might show up elsewhere just don't apply.