To state what is probably obvious, I bet Frank was a nightmare to supervise. Yes, he won, but really, him screaming "eff!" in a way that could be heard throughout the OOD is -- suboptimal? I don't blame Currie for trying to address that to some degree. Curse all you want at practice and at games, but, can you try not doing it in such a way that everyone in the building can hear you? I mean, that's not an unreasonable demand from an AD I don't think.
That said there are a host of other fair grievances with Currie. Specifically, it's Currie's job to do every reasonable thing he can do to keep the talent happy. It's clear to me (especially in light of the Mike Cox situ.) that Currie is a complete failure when it comes to managing his head coaches. To anyone who still had doubts about whose "fault" Frank's departure was, the Mike Cox issue should be all you need to vindicate Frank.