How should I talk about this to my child (trans related)

I want to start off saying I'm a mom who talks to my kid about everything and we as a household are very much like accepting of others and whatnot.

So today my 6 year old saw someone at the mall who was male presenting (full beard, build , etc ) wearing an extremely short mini skirt and very skimpy for black of a better term outfit. I'm very much like an express yourself type person but it was a little shocking just because of how short the skirt was it was a bit unexpected for every day mall attire it seemed more like clubwear or even bordering on lingerie but again I'm not one to care about that sort of thing normally but it was definitely a head turner for anyone lol.

Well ...my 6 year old was rather disturbed by it I guess because he was asking me questions later like "was that a boy or a girl ? Why didn't they have a lot of clothes on ? Why are they wearing girls clothes? I thought that was yucky".

So I'm trying to have the discussion of well they just are wearing what they want to and that's okay and I didn't know if they are a boy or girl and sometimes people just dress however they want and that's fine too. But my child says to me "he looked like a boy so he should probably dress like a boy and not have his butt out because that was gross ".

I'm not sure what to say other than what I already said , if it makes him uncomfortable I understand that too it was a bit uncomfortable because they were almost naked. But I also don't want him to get into this whole boys are only boys crap either like how do I balance this conversation without making him feel like I'm overlooking that it made him feel uncomfortable but also don't want to teach him to be hateful to people that are a little different? If that makes sense. We've had the transgender conversation before and he is 6 so he doesn't fully get it when I explain it and he thinks it's weird like I'm trying to keep it on his level when it comes up but he just thinks it's "gross" but I don't want him to be like hateful about it but also hes only 6 so like idk it's hard i guess. Like I don't want him to be a jerk about it but I also don't want to like force him to be ok with it just because I am and I don't want him to be hateful ?