These folks, by design, are annoying all of the time, but lately, things seem to be getting worse. After being captured on tape spouting an anti-semitic conspiracy theory, Kennedy doubled down with an incoherent gripe about not getting Secret Service protection, which mainly appeared to be an excuse to dog whistle "14" and "88," which are understood as coded signals of support to neo-Nazis.
Unless this is a prelude to going third party, he's not spoiling anything in the Democratic primary. He's probably more of a play to deliver anti-Biden/anti-Democratic-Party messaging.
I think that's just his last name doing the heavy lifting. Once you hear what he actually stands for (like being both antisemetic and supporting Israel no matter what they do), there's probably not a huge constituency.
That's probably why the media is amplifying him and not Marianne Williamson.