FrogReaver
As long as i get to be the frog
Whether you think he's "wrong" or not is irrelevant. That's the official interpretation. You're free to disagree and rule differently when you DM, but then it's a house rule.
LOL.
#1. Not adhering to JC's interpretation is not making a house rule. It may not be going with RAI but going against RAI is not necessarily houseruling (see below for why).
#2. RAW sometimes will provide only 1 interpretation. However, oftentimes RAW provides more than 1 possible interpretation. In this situation if a designers states the rule is intended to be played a certain way and it matches up with one of those possible RAW interpretations then all we have is a designer adding clarity and it should be taken as such.
#3. Sometimes what is claimed by a designer to be RAI doesn't match any of the possible RAW interpretations. As such they are providing a houserule or an unofficial errata or something similar. In these situations they are wrong until something official comes out.
I've reread the actual Improved Divine Smite text on PHB 85 but I'm still struggling even seeing what he is saying as a possibility. If you want to help explain how that text can mean what he is saying that's cool. I'm open to being wrong. But if it's not there as possible from that text then will you admit JC was wrong?