Good observation. Did he drink that beer? Was it even a beer? How do we even know these guys aren't on his campaign bus.
You would think being best buddies with Kennedy that Kerry would be more at ease in a bar setting. Nope.
He needs to stop trying to mimic G.W., it doesn't work for him.
If you look at Kerry's body language, you can see that he is the only one drinking a beer in the immediate crowd. Difficult to say in the whole bar.
The finger pointing down at the bar is an indicator that he is trying to think of a way to 'normalize' his being out of sync with his current "peers".
Note that in another photo, he is holding the beer away from the bar, and low. This, again, is an attempt to minimalize the beer that ONLY HE IS HAVING.
He is not comfortable. He has made a social assumption, that has turned out to be flawed.
Look at his body language. I'm only a patzer - but I can see it. Somebody out there has a great deal more experience in this than I.