Honestly some people just wanna be cute. Guy fashion is pretty fucking bland too, look at the 1000 different kinds of dresses and like the 3 different kinds of suits you can find in a formal clothing store. Also girls don't have as many expectations (at least for physical tasks and some other things) set upon them and in certain settings can get by in life with great ease at the cost of dignity, which not everyone values.
I was personally dysphoric as fuck for the longest time, thinking about this shit, and wanted to go trans, but after rethinking my mindset, drawing some porn with guys in it, and getting complements IRL for my looks, I realized guys can be cute too and that fuckin healed me. At the cost of now being like 40% gay but whatever.