From many of the comments I have seen on this forum, a more accurate statement bight be: "...as far as Catholics are concerned, Protestants are heretical."
The fact is that we all believe the denomination (yes, I am including Catholics and Orthodox churches in that category) we adhere to is the right one, else we would go somewhere else. Some denominations are more willing than others to admit that some of the traditions developed by church leaders have little to do with salvation. This is one of those cases, IMHO.
Jesus commanded us to observe communion in remembrance of His suffering and death. Paul confirmed this commandment, with specific warnings about abusing the Lord's table. There were no scriptural guidelines regarding how often communion should be observed, how long you had to be a Christian before you could take communion, or where and with whom it should be taken. The only warning is that we examine our hearts to be sure that we are not taking communion unworthily, i.e. with unrepented sin in our lives. (FWIW, there is also no scripture to support transubstantiation.)
That being said, if Kerry wants to portray himself as a devout Catholic, he should live up to the teaching of that church. I have partaken of communion at Pentecostal, Episcopal, Baptist, Lutheran, and even Catholic services, following the Lord's command to do so in remembrance of Him, and examining my life beforehand to make sure I do not do so unworthily. But my Christian faith does not prohibit me from doing such - apparently, Kerry's does.
Paul warned us about becoming so caught up in the "traditions of men" that we fail to follow Christ. As far as I am concerned, unless you can show me the basis for a teaching in the Bible, I will respect your right to believe it, but I doubt that it has anything to do with salvation. I think God laughs at a lot of the rules and traditions we try to force on each other.
And you are free to think that, but you will never be a Catholic as long as you do. Not that there's anything wrong with that, for the purposes of this conversation.