He explains Catholicism well. At least a certain kind. What you learn from Catholic education (of a certain kind) is you're mortal and can't be truly sure of much, but if you infuse your actions with love of others, and avoid hate you usually go less wrong if you turn out to be off on specifics.
Another important part of Catholicism that is still important to me is selflessness. Sacrificing for the greater good.
Protestants dislike this 'good works' part because they think we could never deserve salvation but Colbert talks about what it's SUPPOSED to be--it can make life more meaningful to always try to do good for others. I mean, we have to do SOMETHING with our life, right? So why not that? Life is short