Does saying women have been sexualized and be allowed to show their underwear and asking how is it unprofessional count as femnazisism?

Basically my friends and I were having a conversation and they started ranting about how girls should be allowed to roll up their school skirts and that society was sexualising 11-16 yr olds and their underwear. I disagreed and I pointed out they don't let us do it because it's unprofessional. They started saying yeah, but why is unprofessional? Because it was sexualized. We then had a massive debate (argument). I don't believe in sexualising women, but I do believe that all genders should try and looks smart, whether in an office or a uniform, because it's work or you're representing something. I don't think it's professional to show your underwear, regardless of gender. I stood by this and I kept repeating what I said everytime they said, 'but why?'. In the end, there were some ugly accusations (are you supporting the sexualisation of teenagers?!) and I'm just wondering, does this count as femnazism?