• In https://lemm.ee/comment/20947041 they claimed “implicit type coercion” and showed many examples; they did NOT claim “string concatenation”.
• However, that was in reply to https://lemmy.world/comment/17473361 which was talking about “implicit conversion to string” which is a specific type of “implicit type coercion”; NONE of the examples given involved a conversion to string.
• But also, that was in reply to https://lemm.ee/comment/20939144 which only mentions “implicit type coercion” in general.

So, I think probably everyone in the thread is “correct”, but you are actually talking past one another.

I think the JS behavior is a bad design choice, but it is well documented and consistent across implementations.