Why do men say they are single in their tinder bio even when they're not?

I've seen many men straight up say they're single in their tinder bio. I always swipe right on them because I have no reason to not do so but I always get messages from their partner or their friends after a few dates saying they're actually in a relationship.<br><br>I'm not stupid, I'd never date a man who is in a relationship but I'm just confused as to why these men say they're "single" in their profile then later on tell me they have a girlfriend etc.<br><br>Is it to not scare away potential matches? But it can't be that hard to just say "I have a girlfriend but would like to try open relationship" or something similar. It feels like they're trying to trick people.