Actually, it's not.
Being banned from communion means that you are in a state of mortal sin. Indeed, since Kerry's first marriage has not been annulled, he shouldn't be receiving communion, since he is living in sin...there is a line from Paul that says you shouldn't receive the bread and wine "unworthily"...
For all that is written about JFK, I remember back then he never went to communion, although he usually went to church...so when I heard about his girlfriends, I figured that was the reason why...Kerry doesn't have that problem. He obviously doesn't think receiving the bread and wine is receiving the body and blood of Christ...imagine meeting Christ and saying: Yes, I am your follower, but I will help people murder babies if they chose to do so....