Every hard and soft fork is an example of "rules that were set in stone since 2009" that are no longer followed.
The core money property rules have not changed, although I agree that the place where we draw the line between what is "core money property" and what is a simple network rule is a little vague. SegWit could also be considered partially a change in the underlying economics. However, I think it is completely clear that any change in the monetary policy of bitcoin should be objectively considered a "core money property" change.
More importantly, are you advocating that changes to the Bitcoin protocol should not be discussed?
Absolutely not. I don't see where you got this.