and fails to provide any explanation that is meaningful as to why they refuse to perform their obligation.
Except that they did provide an explanation, they inspected and determined that the camera had been damaged by the user. I'm not saying that they are right or wrong in their assessment, but they did tell you why they are denying the warranty claim.
If they took anyone at their word that a product wasn't dropped or otherwise damaged by the owner, it wouldn't be just $100 as you stated, it would be millions because everyone who dropped their camera would send it back and claim "it just suddenly stopped working".
Telling the user they are a liar is not a *meaningful* explanation.
A *meaningful* explanation would be something like "the reason it zooms to the long end by itself and then you can't control it is because the ____ is broken (or malfunctioning). This typically happens because ____."
At a minimum, a *meaningful* explanation acknowledges the symptons, identifies a tangible cause, and postulates a reason why it would happen.
When I hear "you dropped it" as the only explanation as to why a cosmetically mint camera that hasn't been dropped isn't going to be covered, the most likely explanation for that is that they probably didn't bother to even inspect it beyond maybe turning it on and seeing that its malfunctioning.