I've tried watching it but give up at around the 10th F-Bomb which appears in less than five minutes.
My theory: the scriptwriters are wusses who try to show their "manliness" by causing the characters to F-bomb constantly for an hour.
Like prior years, I'll cancel HBO when the Sopranos' season ends.
Actually the script writer is trying to establish how uncivilized Deadwood was at that point in history and how rapidly it changed. If HBO gives him enough seasons the intention of the show is to DRAMATICALLY clean up the language and look.
David Milch, the creator of "Deadwood," has quite a foul mouth. He's interviewed on the DVD, and your theory fits. Like everyone else in Hollywood he wants to be a "rebel" and an "iconoclast," but he only succeeds in sounding like a typical movie industry pseudo-tough guy.
Milch is a very bright guy, too, but his characters don't come to life as much as those on "the Sopranos" or "Six Feet Under." They feel more like intellectual constructs than like real people, at least to me. Whatever else one thinks about the Sopranos, the first seasons brought something new to television and had a feel of authenticity.