After all his years at the National Schismatic Reporter, he is probably very well paid, and there's no other Catholic paper or magazine of which I am aware that could afford to pay him a major columnist's salary.
With that said, at some point a fellow just has to say "No." Everybody has a point beyond which they will not go -- and given the poisonous anti-Catholic rhetoric that NCR puts out on a regular basis, if I were in his shoes I would have reached that point a long time ago.
It is easier to say that before you are already in the soup, though. Many years ago, when I was unemployed, I was offered a job and the money was very good, but I asked the advice of an older lawyer that I respected very much, and he said NOT to take the job -- although he said "I can't tell you why - but don't take it." I didn't, and I was glad afterwards. And I won't tell you why either. :-)