I think he hates most modern episodes of SB because of the most common reason people hate new things: nostalgia.I actually enjoyed the Splinter episode. The ending joke was painfully unfunny, though that's been said before.
I think that he needs to stop claiming that modern SpongeBob episodes are atrocities. The sad truth is that a bad SpongeBob episode is usually better than a lot of other show's best episodes. I think that the problem is that because he likes SpongeBob he sets the bar for every episode pretty high. When the episode fails to meet his expectations he hates it more than he should because of that.