Honestly, I love it! It shows that the guy isn't afraid to put himself out there, and to show who he really is, and what he really likes.
I grew up with a gay friend. He would tell me he liked girls, but his actions, his moves, his way of speaking, and his hobbies all suggested otherwise. Him and I got along really well, and used to be best friends (we still speak from time to time now, but we live faraway from eachother). Now, it has been a long time since he came out of the closet, and he is nothing but confident. He once showed up at a party wearing some kickass eyeliner, and though alot of people were laughing and staring (yes the guys, the guys) he didn't let anything bother him. He was the life of the party.
I'm very open to guys buying makeup. Why should it bother me, or anyone else for that matter? You are who you are, and if you love makeup, then all the power to you! The best makeup advice, and the best fashion advice that I have ever received has come from males.
Which counter do you shop at? Do you live in an area where people are close to these type of things? If so, then don't be surprised at people looking at you strangely. They aren't used to it, and to have that type of behavior coming from a man is very "abnormal" to them. It is also because of these people that your rights aren't being recognized.
Don't feel bad if you get evil stares. Be confident! The minute someone senses you aren't comfortable, they will have the nerve to talk to you about it, and comment on the makeup you are buying.