I Am So Confused

So perhaps I'm just naive because of cultural issues or something but is a woman that is friends with a man automatically sending a message to that guy that she's interested in him?

I mean, this is the 4th or 5th time I've had a guy tell me I friendzoned them.But I never hide the fact that I'm married and openly state it, I don't flirt knowingly and stop a convo if it starts,I say outright I'm just friends with my guy friends and I treat them like brothers just like my girlfriends I treat like sisters.....

What am I doing wrong? I'm just going to never be friends with a guy and just be civil instead. Much easier.