As far as I know, the FCC regulates only broadcast media, and since basic cable is not technically "broadcast" (not OTA), networks like FX, TBS, and AMC do not operate under threat of FCC sanctions and fines, like regular broadcast networks. So the censorship they impose is basically voluntary.
They've decided (probably quite wisely) to push the envelope only a little bit further.
On the scripted series, you'll also get the occasional quick flash of a bare female breast. No full frontal nudity, but occasional full 'backal' and full 'sidal' nudity....so to speak.
And unlike premium channels (HBO, Showtime, etc.), you won't hear the 'F' word or see any genitalia.