Going out of your way to kill technologies that compete with your proprietary social network qualifies as evil in my book.

"Not going out of your way to support technologies you aren't interested in" is not the same as "Going out of your way to kill technologies that compete with your proprietary social network".

But when not supporting these open technologies very obviously benefits your proprietary social network, it is.

Okay, then Dropbox is evil unless they support open file syncing technologies?

If they are trying to shoehorn every man, woman and child into using their social network in a bid to track their respective activities in so as to sell the information to the highest bidder, yes. As it stands, Dropbox aren't so no they are not evil.