Seems more like they're trying to get abandoned accounts down to $0 in their wallets so they can cancel all the abandoned accounts wasting space on their server than actually trying to charge people a fee for something.
Not to mention that almost every bank has fees too. Overdraft fees are charging you because you didn’t have money!
People literally just give up on their PP accounts, because it's not worth your sanity (dealing with Paypal's "customer service") for something like $100 left in the account.