I've seen several times already in some conversations dedicated to shit on men, statements either implicit or explicit that there are more single men compared to women.

There are more women than men, if we define relationship as 1-1 pair then there are more single women unless there are lots of lesbians.

Polyamory/polygamy. A lot of these are barely relationships, it's not that easy to go out and stuff with several people simultaneously which just leaves casual sex(or which is not often living with several wifes). So I guess if someone visits a hooker he can no longer be considered single?

The same goes for whether you are a virgin or not(what they probably imply). Again I guess if someone visits a hooker is not single either?

Then single mothers, a lot. I guess if someone came in you once then you are not single anymore? Guess if I had sex in the past I'm no longer single aswell.