The robo-calls were not for advertisements, they were for collections.
IE - you would get a robo-call saying your bank account was overdrawn and you owe Paypal $5000.
The only difference between what Paypal wants to do and what all other collection agencies do is if a human is on the other end of the phone.
That's what PayPal claimed when the backlash against the new ToS began. But the ToS specifically included polls and telemarketing as their allowed use of robocalls. I cancelled both my PayPal and eBay (which has nearly identical terms of service) over this. I think they could probably eliminate most of the user backlash by removing the advertising clauses from their terms of service, notwithstanding any federal regulations that might still restrict their use of robocalls.