I would say that it’s less about the allegations of antisemitism in general and more about allegations that turn out to be untrue. A lot of (very abusive, shitty) people can point to allegations proven false as evidence of no wrong-doing in the future, which can create a more dangerous space – this was my argument against Wikibara’s inclusion of the link between their application being denied and antisemitism in their original post.
When I worked in in-patient court-mandated substance abuse recovery, there was a white supremacist guy who told me tales about how he would get fabrications of abuse, which could easily be proven false to create a protective shell. “I don’t abuse my partner, she said I abused her and everyone found out it was bullshit”, which then gave him free rein to kind of abuse whomever. After all, people are lying to discredit his character. I stopped being interested in correctional psych after that, if I’m being honest. Moral injury and all.
According to my (very uninformed, very amateur) research, this is apparently called a “silver bullet” in the legal field.