Religious discrimination at work

A recent article I'd like to comment on, or rather to provoke a broader discussion: Hijab-wearing Muslim woman sues Disney over dress code.

This is only one example, and I'm certain you can find atheists who do that same sort of thing, but this is a kind of discrimination that just doesn't really seem like discrimination. In my last job, for instance, I was told I needed to not wear my skull bandannas, because they were against the dress code; I had similar issues at my job before that; and as a vegan, I'm certainly never going to get a job at a place like McDonald's. Why are the issues any different when religion is the excuse, instead of one's ethics or culture?

The courts in the U.S. have tended toward "accommodationism", which essentially means that the onus in on the employer to show that an individual's religious practices prevent them from doing their job effectively; if you can do your job effectively (whatever that means, given the circumstances), you get an exemption from the rules.

This seems to me to be a big, big can of worms - who decides what "effectiveness" means? Who decides what "a sincere religious belief" is?

And this is only the start of the issue - what about more gray areas like Harvard's decision to set aside women-only hours at the gym after a request by Muslim women, for example. If you can give people permission to leave places they don't want to be because it's there religion, can you give them special access to places they do want to be because it's their religion? What if these were evangelical Christians who wanted all the gay men to leave the gym, instead? Would that be acceptable? And granted, the request the women made at Harvard was incredibly modest: just 6 hours out of the 70 hours the gym would be open, and it was only one of apparently several gyms Harvard has - but if it's only a liiittle bit of discrimination, does that make it okay?

Maybe I'm just being a simpleton here, but it seems like so many of these issues are so easy to rectify by giving religious people the same rights everybody else has, instead of their current special privileges.