I think it gets pretty hypocritical, singling out religion like that. In the workplace, I can have memorabilia of my favorite sports team even though someone else hates it (unless perhaps it's a Catholic School team that has a cross in its logo?). I can have the flag of a hostile foreign country because I'm proud of my heritige. I can have a picture of me kissing my wife even though it would normally be just outside the common no-tolerance Harassment policy. Unless it was taken at the wedding, or in/near a religious monument. I can wear gauge earrings, or just a little star... as long as it's not a Star of David. Ditto with pendants, even new-agey wooowooo pendants, as long as it's not a pentagram. There's no path there that isn't hypocritical.

Freedom of religion and freedom from religion go hand-in-hand, and it's not always an easy relationship to figure out. Forced private secularism is its own anti-freedom problem, even when discussing the employee at a government workplace. It's not really secular if I'm forbidden from wearing something for solely religious reasons. Even if the religious reason is that the thing I want to wear is religious.