Usually true but there are schemes to launder money to a place from an upfront “clean” operation. The IRA was/is genius at that.
Your scenario has a federally disclosed political money account being used as a means to seemingly pay for catering and event services but in actuality to funnel money to a child molester operation. While such a transaction has the virtue of creating an apparently legitimate basis for reporting the payment to the IRS as an expense to the payer and income to the payee, it also creates a public connection from the payer to what is assumed to be an especially nasty form of criminality. On the whole, balancing risk and benefit for both sides, cash would seem better.