Let's say you were trying to rationalize why a company's "extreme growth hacking coupled with a psychological approach to user acquisition" was actually good for the world. It's usually not that hard if you want it. Company X provides something that is (arguably) important (to someone), and the marketing means help it reach people.

So I tried to put on this hat for a minute, but I cannot for the life of me even intentionally come up with a justification for BuzzFeed.

Even if you believe whole-heartedly in general that the end (company getting its service out there) justifies the means (marketing, manipulation)... with BuzzFeed the end and the means are exactly the same thing.

It's got all of the societal value of the Jerry Springer show: It's garbage for the sake of providing space to sell garbage.