Can a gay guy kiss girls?

Hey everyone, I would like your honest opinion. Basically I know this guy who says he is gay but I'm starting to have doubts about his orientation. I totally believed him at the beginning but he acted sketchy at a party with coworkers. So at this party he decided to lip kiss all the girls because he said "I'm gay and it doesn't matter". Many girls accepted the invitation. Do you think it's sketchy and he is playing all of us? Or is it normal for a gay guy to lip kiss many girls at a party? Thanks in advance for your opinion.