This is how I feel about LinkedIn. I've seen so many losers and fuckups (people I've worked with who have destroyed teams and companies) with large numbers of tit-for-tat, glowing recommendations and ridiculous endorsement counts. I haven't played that game (and have an extremely boring LI profile, with past employers not listed) and my numbers are embarrassing.
It's more like the "tragedy of the uncommons": bland people fighting to establish themselves as somehow special or superior, and fucking up everything for everyone. It just generates noise, and the winners are the people who are best at making the right kind of noise.
LinkedIn also tricked a generation into giving up one of their most important professional rights: the right to reinvent themselves. I use it, because the information is useful, but I feel like the world was a much better place when professional oversharing wasn't expected. When labor overshares and capital doesn't change what it does, who should one expect to win?
As far as I'm concerned, I don't have an ethical problem with social proof arbitrage. Even if I did, that'd just mean losing to others who don't follow such rules. The main reason I don't do it is that I don't care. I'm apathetic about "social proof" in general because, in humans, sociality is inversely proportional to quality. I certainly wouldn't want to work at a job where the difference between a 2000 and a 6000 follower count mattered.