I don't want to cast judgments on the man, as it's not my place, and I don't know the circumstances.
In his profession, though, I think--beyond the matter of trying to punish him for a crime he was acquitted of--the Rams would be justified in letting him go if they believed his ability to coach players in this locker room would be undermined by the events that occurred, which may well be the case. Personally I would not look at a man the same way once this came out, acquittal or no. Depending how Rath may handle it moving forward, I could see him winning back the respect of the people there, but the lapse in players' ability to trust him on a personal level would be a valid reason for letting him go, IMO, and ultimately brought on by his own irresponsible behavior. So yeah, I think it's just a judgment call for all involved.