Don't know if is an attempt to avoid honoring the Buyer's Protection, but it is my understanding that eBay is rather aggressive in eliminating negative feedback on sellers and has been doing so for quite some time. They probably have an algorithm in place that alerts them to a higher than normal negative feedback and act accordingly to policy (whatever that is).

Note: I am registered with eBay (but never used) and I've used Paypal only once (for a third-party vendor that wasn't even listed on eBay).