We actually are not analyzing the guilt of the accuser, only of the accused. You really have to focus on that.
The moment you make an accusation, the person you accused gets to make an accusation back at you, that you're lying and slandering them, so now you're also someone who is being accused of something.
Your "believe the victim" attitude is contradictory because it necessitates believing the assault claims and the slander claims, simultaneously, which is a paradox and can not be. Unless somewhere deep down you don't consider people who are slandered as "real" victims or something.
No. The police, and society in general, do analyse the potential guilt of the accuser. In every single case
For example, in a rape case you HAVE to prove that a rape happens. In a theft case, you HAVE to prove that a theft happened. In a murder case, you have to show a body.
And I do say potential guilt because maybe the accuser is using the wrong terminology or it doesn't reach the bar of a particular crime. So they might notbe guilty, they may just be wrong. Eg. Hunter Biden earn a bunch of money off his father name/position. At this time, there seems to be no collaboration to get policies through so Hunter can score big. (The GOP did a 87 page document saying as such.) That doesn't mean the whole situation isn't dodgy and maybe would SHOULD make laws to stop this from happening. But the current accusations don't reach anything criminal.
This is separate from the Hunter tax evasion where there is evidence of him breaking the law. The same accusers are right about one case and not the other. Nor do I think it's wrong for accusers to question Hunter's business dealings, even if it ends up not being criminal