Not so much rejecting the renegades, as the NFL having changed.
Players like Matuszak, Stabler, et al, would not have survived in today's NFL (not if they had carried on the same way as back then).
I think its more Al Davis waking up to the fact that the NFL is more image conscious than ever before. Players find it harder to get away with anything because the media has to fill time and looks for the misdemeanours of players (and other public figures). There is also way more money and thus the expectations are higher.
I think he's also realising that many of these "bad boys" are just not good workers and have a detrimental effect on the team. When the Raiders solidify their talent with togetherness and hard-work they'll have a better chance of winning. I'll say one thing for the Raiders (and Al Davis and Tom Cable in particular), they've made some solid steps in the right direction in this regard. Its now up to them (Al Davis) to see this through.