H4run
Deity
I think it's more complicated than that.
Visualisation of a text is definitely not a simple matter. What works in one medium may not work in the other, so there should be no inherent expectation that nothing is changed. The argument should be about whether a particular change works or not, and even then there may be considerations other than plot or characterisation (e.g. times have changed, run times, realistic budgets, casting issues, etc).
Sure, in that regard I agree, it's not technically easy to adapt the text to the screen, fans must be wise and grow up enough to acknowledge the obstacle. I was thinking more about blatant changes in the work, like changes in race or gender, or whatever, I'm not surprised when people got really pissed when Rowling want to re-imagine Hermoine's as black, that's because this work is not simply owned by Rowling, but this has already become an integrated part of many peoples experience, it's already owned by the crowd and fans that perhaps more well-versed regarding the canon more than Rowling herself, and the re-imagination of it can cause people to become really or even extremely not comfortable