Why every gay bar owner in yaoi have to be called mama

I'm guessing because, since they own the bar, they are like a mother that's looking over her gaybies

Although the mom thing is a cuter reason, it's because brothel or bar owners managed by females are called mama-San but in gay bars they still call the male managers/owners/bartends mama because they like men or you can earn mama title by giving out the best advice ╮(￣▽￣)╭

Mama here isn't related to the word mother...kaa san. It's literally the word Mama San which means bar owner or cat house owner in term of the owner is an uke or females and prefer this title. If the owner, bartender is the seme or male, it could be Master for instance. All of this depends on the person preference and would be known when self introduction.

Ohh thanks