Bars/clubs are optimized for making people go home with a hole for their peg or peg to fill their hole. There's a lot of bad matches but if you test drive enough pegs/holes eventually you find one that belongs to someone you are compatible with.

It's the Red Army circa 1945 approach to dating. Throw enough bodies at the problem and eventually one of them will be the one that solves it.

If you want to make fewer higher quality matches don't go to a bar.