I think much of what people are objecting to is that, by virtue of its position as an _invite only_ paid service, it provides insight to only the employer party

I think much of what people are objecting to is that, by virtue of its position as an _invite only_ paid service, it provides insight to only the employer party of a two-player game. It is apparently purpose-built to allow only the employers to arbitrage that extra insight into hiring patterns.