Personally I don't think it's all that big a deal. That being said I do despise the double standard and disingenuous spin and excuse making by the MSM and Obama campaign. If a republican would have been in similar circumstance he'd (or she'd) have beeen pilloried.
He made an inference joke (a lame one) and knew exactly what he was doing. It pushed the envelope but, hey, politics ain't beanbag. One of the few times I'll ever use this term but "move on".