Basically, Paypal doesn't want you making any type of class action suit against them.
Thankfully, there's something that you can do about it. There's a form that you can download, fill out and mail to them that allows you to opt-out of this nonsense. You can get the form here - Here Is A Downloadable Template For Opting Out Of PayPal Arbitration Clause and you have to mail it to Paypal before December 1st, 2012.
Hope this helps!