Okay friend so as a person who is nonbinary I feel as though it is not rude in anyway to me. I also believe that for some they may ask you to know that they may present one way but that does not mean they are all about the girl side. I know in my case I do not present femme but I feel that it is just me. You may want to note that most would not want you to consider them femme-presenting. I know from my own experience that you can never know how someone truly calls themselves even if they present one way or the other so keep that in mind as you go about it. I believe that you are just attracted to that feministic side of people so that is fine it is not that you are picking them completely on how they dress. I know for myself I go for the more masculine presenting side of it. I do not see that this is rude in any way but do know that I am only one answer to this question you ask. Hope this helps in some way. Sorry I could not completely answer your question but really it is a personal question for each person. 

Melody