Eh, I think we understand what "theft" means in this context. It's "theft" more in the "theft of service" or "theft of value" sense: Buzzfeed has taken something that would otherwise cost money to use and has used it without payment ("theft of service"). And has potentially sapped value from it by making it tougher for the author to use as he wants (like in a book -- "theft of value").

"Theft" works, here.