What Hurtnell did must've been far worse.
Lance Parkin has a fascinating... well, I'm not going to call it a theory because it was a throwaway line on Gallifrey Base.
The Hurt Doctor fought the Time War on the side of the Daleks.
This makes a lot of sense, given what little we know of the Time War and it fits well with what we see in "The End of Time" where the Rassilon's inner circle is terrified that the Doctor has "The Moment" (why would that terrify them if the Doctor were on their side?) and the Doctor is terrified that the Gallifrey has come back. This would explain why the Time Lords resurrected the Master -- they needed a rogue element to counter the Doctor. And this would explain why the Doctor saved Davros.
If true, it may have been an alliance of convenience for the Doctor. He saw his own people go power mad (shades of the warning he offers in "Trial of a Time Lord" 13), and he made the judgment that the Daleks were the only force in the universe that could counter a militaristic Time Lord society.
And then, of course, the Doctor betrays the Daleks, using them to get him in a position where he can use The Moment and eliminate both sides.
The Doctor can still be proud of what he did to the Daleks, the Daleks can still fear and hate the Doctor.
It's a workable idea.