No, I don't think there is such a right. Which is why I think the relevant question here is social congruity. It is bad for a society - both in terms of its stability and in terms of its combat power - to have a military that civilians don't buy into. That's why I gave the (distinctly American, I know) example of allowing non-white servicepeople. While it would be problematic to lose the non-white servicepeople currently in uniform (roughly a quarter of the service), I think it would be more problematic, at least in the long run, for America to feel like its military was a bastion of racism - even if it was a bastion of racism in the name of promoting unit cohesion and morale. A military doesn't need to be in lockstep with civilian culture, but a situation where civilians don't respect the institution is not a good recipe for maintaining combat power, let alone social stability. In America, at least, I think we're at a turning point with respect to civilian will and women in combat arms, and I think that's a very military thing to consider.