My impression is that the main problem with going to a catholic college is the avoda zara all around. You have the same problem with a catholic hospital.
It seems to me that it may be less of a problem than pritzus. But of course, one should ask a sheilah as they should before attending any college. And anyone who is considering going to college should look into the pitfalls of all 3 options (Jewish, secular, or catholic), and make sure he is aware of all the problems with each option before he makes his decision.
Each option has advantages and disadvantages. Some would say that one is better and others would say another one.
Whichever one someone ultimately chooses, he should make sure that he knows what the problems are and how he can try to avoid them.