It's six in one and a half dozen in the other. Banks only care about sex trafficking because sex trafficking is a crime and processing money from criminal activity is... money laundering. But regardless, what's the risk of sex trafficking here? Again, these payments are coming from and going to known parties. In fact, this should be a KYC dream come true. Because of the adult content OnlyFans collects (and in the case of payment recipients, confirms) the name, DOB, and address of everyone buying and selling on the platform.

If human trafficking were the actual risk banks were trying to mitigate here then it would be difficult for any business sector that relies on migrant workers to obtain banking services but I've never heard of an almond grower having trouble opening a bank account.