If you say, "Ah, my party will probably only be three of us, I better pay 100 people to stand around so that I don't look bad", do people normally think this is an honest practice? You're still perpetrating a deception that could have real consequences.
Sounds fascinating to me
If it were a dating site and the founders filled it with a bunch of fake profiles with pictures of models, then I would have an issue with it because I'd feel the user is being taken advantage of. If there's a fake profile submitting links to news stories, there isn't much of a victim.
ADD: sure it's unpleasant, so let's just downvote and stay happy.
"Heavy weighs the head that wears the crown"; when you lead a large entity, there are always going to be people that are unhappy with your choices. I think by and large the great majority of businesspersons attempt to conduct business morally in general.
These are social sites and subject to the same kind of first impression biases that we all face in person.
Imagine showing up at a party with 2 guys sitting on a couch talking to each other compared to a party with people out front talking, people inside dancing and a small group in the back yard sharing a laugh. Social proof matters & I'd hardly consider this cheating or slimy.