So, rather than recognizing that the other agent had been extra nice granting him a privilege, he disparaged the one who followed the rules.
Which is his legally protected right. She's acting with government authority (which she doesn't actually have) in demanding he remove the comment. She doesn't have to authority to remove him from the plane -- once he's allowed past the gate, he's allowed. She can lie to TSA or the pilots and claim he's a threat to get them (who do have the authority) to remove him -- but doing so is a very big no-no (felony.) (not that anyone in their circle would do jack about it. just like the PR hand wave SWA is doing now.)