This was a question that I had and it's been answered. I couldn't find anywhere yesterday that the league had upgraded the foul to a flagrant, much less to a flagrant 2. It's the contact to the head that warranted the suspension, not the classification of the foul -- the two things are separate.
For instance, Juwan Howard was given a flagrant 2 and ejected for his foul on Derek Anderson in 2001, but he wasn't suspended for the next game. Kevin Willis was given a flagrant 2 and ejected for a foul on Scott Williams in the first game of the Phoenix series in 2003, and he was suspended for the next game. Willis' foul involved a head shot; Howard's did not. I'm sure that there are other examples of head blows that haven't resulted in flagrant fouls but have been met with suspensions.
I still think the punishment is excessive and would agree that Artest is being judged more for what he did in the past than what he did on Saturday, but I think the implementation of a suspension for a blow to the head is fairly consistent.