I fear there are no men of conscience left in DC. It is all about ego and pettiness.
McCain played nice and sucked up to 0bama so long as he got the ego stroking and attention he needed. Now, someone has ticked him off, so he talks tough for a few minutes and gets some air time and media attention. That will feed the ego for a while and he will forget about this until the next time someone fails to stroke his ego.
Although McCain did say tonight that Benghazi is a centipede that has many more shoes to drop. Maybe McCain will stay focused.