You are right on the matter (cause having p4 vs Churchill is in favor of Churchill obviously) the reason original author claimed was differ.
I wanted to point out irony of clamming 240 armor as "bounces off everything" (180 in fact, because he claimed "rear") when we are speaking about one of the highest(312) armor unit in this thread.
Sorry, first thing was a typo. I meant you DON'T need a TD to stop a medium in contrast to stopping a Churchill where you need one.
The 180 rear armor is important because flanking with a medium won't help much. A mid range P4 still bounces a third of its shots.
If you flank an OKW P4 even with a T34 you will do damage. Overall, other mediums and ATGs can therefore be threats to mediums, but can (not have to) be unreliable vs the Churchill unless amassed. That's why a TD is your best choice. It is the same with all heavy tanks and unvetted ATGs across all factions, although heavies already got their rear armor reduced to allow for exactly that flanking damage.