This does not seem to be accurate. I couldn't find anything in their TOS other than reasonable sounding restrictions on what can be sold. Sorry. https://www.paypal.com/us/webapps/mpp/ua/useragreement-full https://www.paypal.com/us/legalhub/acceptableuse-full
To my view, there's a world of difference between "You can't use PayPal as a payment processor for gun sales" and "You can't use PayPal to pay pals back for covering your range fees last Saturday."
Yet the AUP seems broad enough to cover both: "You may not use the PayPal service for activities that... relate to transactions involving... ammunition, firearms, or certain firearm parts or accessories...." https://www.paypal.com/us/legalhub/acceptableuse-full