I thought this same thing. Hard forks probably do carry an inherent negative impact on a coin's value. But depending on the reason for the fork that impact could easily be overshadowed by a positive response. I think this factor is coin/situation dependent.
I do not agree it is inherently negative. In fact a coin where developers are unable make important changes (including hard forks) for whatever competence, organizational, or political reasons could see its value decline for that reason.
So I agree what what you said about it being coin/situation dependent.
Hard forks done for bad reasons or which are poorly executed will hurt a coin value.
We may just agree. My statement that a hard fork has negative impact is meant it is implicitly negative when viewed alone. An analogy is the surgeons scalpel. It is going to leave a scar, but under normal circumstances that impact is overshadowed by the value of the surgery.
A question. What circumstances would a hard fork in BITCOIN not be viewed as negative by a significant percentage of users? In my opinion there isn't one.
Monero and other alts have an advantage of being younger, and less established thereby reducing the impact. We can get away with more for now. And I think the more established the platform, the more -EV effect when there is a fork.
But if/when the devs choose to fork Monero there will be downstream issues. We cannot pretend othewise.