Please cite specific gyms, clothing stores, medical centers which refuse to business with men for services that would be applicable for men. For everyone you post, I'll likely be able to post an example of the same type of business being sued and winning a discrimination lawsuit.
I'm not going to name names as they're pretty common around here -- fitness centers that advertise that they are only for women. Just google for "women-only" and you'll find all sorts of generic services aimed at women -- and a McGill University issue regarding a fitness gym and arguments for/against having gender-exclusive gyms at a university.
You look at their websites and everything they say (other than "exclusively for women") is just as applicable to men as to women. Unless you believe high-low and yoga classes are somehow incompatible with the male physique.
That said, I have no problem with women-only gyms (or men-only gyms). This is discrimination that in my view is perfectly acceptable, as it's based on real issues in our society, and is preventing negative fallout due to those issues. I'd have issues with a gym that segregated based on skin tone or native language though.
Hey... I've been into lots of high end retail stores in my casual clothes where the clerks have refused to even acknowledge my existence -- I figure they saw a guy in cheap department store clothes and figured I couldn't afford to shop there if I wanted to. Never bothered to press charges, but I guess I theoretically could have -- but it would be hard to prove anything (although security footage would help). Easier just to add them to the list of places not to spend my money, and reward the stores that DO want my patronage.
Where the problem really exists is when (like with Verizon/Comcast) there's really no other alternative service you can use. In these cases, if EVERYONE is discriminating based on sexual preferences/gender/melatonin level/perceived wealth, then individuals are being locked out of service, and that's bad.