I'm going to keep flirting with women that have already been taken
Why would you do something like that?
It's fun; I'm just being nice.
You might think your being nice, but it's crossing a line. It shows a lack of respect for their relationship and their boundaries.
It's alright, if they don't like the flirting, the guys wouldn't be with them anyway.
You shouldn't flirt with women you know are in a relationship. It's really disrespectful and shows that you don't actually care about them.