If you look at the links on the site, it's pretty obvious the folks behind it have an axe to grind with PayPal. In this case, it appears to have been a $10,000 axe. It's a collection of links to bad experiences with the service.
For myself, I've never dealt with PayPal because of the "electronic notification" clause in the TOS: it's up to you to continually inspect their website for (binding) changes to the TOS, they don't have to notify you separately.
And a website I'm the admin of refuses to deal with them because of the wide-open "reversal of payment" clause. Looks like that's also the one that caught out quite a few of the complainers on the site you found.