First of all I have to say I love the show. It's one of the funniest shows I've ever seen. Secondly, I personally wasn't offended by this episode and I don't think it was meant to be offensive or catch anybody off-guard. First of all he didn't urinate on the picture of Jesus per se (or however you spell that word), the premise was that he was taking some sort of pill which caused him to pee a lot. And when he would go to the bathroom, it would sound like a high pressure hose was going off in the bathroom because he really had to pee. It was hard for him to control it and it would kind of splatter back into the air and a drop landed on the picture of Jesus in the bathroom which made it look like Jesus had a tear in his eye. Larry contemplated wiping it off but he chose not to (I think it was trying to lead you to believe that he didn't want to wipe it off because he didn't want to get urine on himself), and thinking it was no big deal and that it would dry off or something, he left the drop of urine on the picture. I don't find it offensive because it obviously wasn't real pee, he wasn't pretending to pee on it deliberately (it was just a drop), and if you have seen how Larry acts on the show, you would understand why he acted the way he did, contemplating if he should wipe off the drop or not. And I don't think it was trying to poke fun at Catholics at all. It was just trying to make a silly situation like there is in all of the episodes.
Having said all of this, I did not enjoy the episode that much and thought it ranked with the worsts of the episodes purely for the over-the-top silliness and lack of humor that is in just about all the episodes. I found parts of this show amusing but for the most part way over the top and more silly than funny. But I was not offended and I don't think they were trying to be offensive at all.