Unfortunately, to many on the left, the political is moral. David Horowitz, the director of the Center for the Study of Popular Culture, stated that politics to the left is a religion. For them it is as impossible to separate liberal politics and morality as it sometimes is for many on the right to separate religion and morality. One is a foundation of the other. Religious conservatives believe that God is the foundation of morality.
Liberals believe that their politics are the product of morality.
So, when you get a demagogue like Bill Kelly, it only follows that his beliefs run counter to leftist attitudes. Bill Kelly is immoral, and people who are immoral are Republicans, ergo Bill Kelly is a Republican. After all, there are no mutants in real life, nor do we face these issues in the real world. We should all care. It displays the mindset of people who have tremendous influence in our culture.