The term "enabling PVP" was suggested by Tumblr users because of the aggressive attitude the community would have towards sponsored posts. As you can expect, nobody wants to spend money to be harassed, and terms like this turn people off spending money on the site.

I don't understand why Tumblr admins embrace the factors that make spending money on Tumblr bad, instead of culling the free users who attack paying users. It's not even like the remaining Tumblr users can revolt. They're hated by the rest of the internet, they don't have anywhere else to go and they don't have the tech know-how to set up their own site. Tumblr can't expect to maintain their "unique website culture" and make money at the same time.