It is only painful when not properly lubricated.
Yes, the voice of experience speaking, going out is not nearly as painful as going in. The patient had already experienced it going in, so the pain should have been much less. As some have pointed out, if the balloon which anchored the catheter in the bladder was not deflated it would have been exquisitely painful, if not severely injurious. But, unless it was deliberate, justifying the attack on the nurse, no.