An "early out" is not desertion. He went through proper channels and the military both transferred him and then released him. I could never fault a military person for availing himself of any legitimate means of opting out of active combat. However, Kerry has opened this door with his assault on Bush, and he can hardly complain if others walk through it.
We still haven't gotten a source of Kerry's "assault on Bush" or him calling Bush a deserter. Do you have one? I would be interested to see exactly what he said and in what context.