What if the flip flop were on the other foot?

No surprise that Sen. McCain opposes the adoption of children by gay folks. The bigger surprise is that he flip flopped on the issue

If this flip flop were on Sen Obama's foot, the McCain campaign would be all over it, suggesting that Obama was flipping in face of pressure from an interest group. Gay civil rights groups, even the Log Cabin types aren't usually the type of group Sen McCain cares much about...so why the flip flop? To appease the state's rights types?