I think part of what's making the conversations around the casting choices in the live action HTTYD so annoying to me is that for me, it has nothing to do with any of the supposedly controversial casting and more to do with the fact the movie seems to be cherry-picking what it wants to carry directly from animation to live action.
We have to wait to see more but as of right now, it looks like a near shot-for-shot remake. I know the director, Dean Deblois, said it wouldn't be but he was also on record of saying he would never make a live action remake and called them lazy several years ago but here we are so forgive me if I don't completely take his word on that. They did their damnedest to make poor Gerard Butler look as much like animated Stoick as humanly possible even if it means it looks like he just walked out of a Spirit Halloween store. Hiccup looks pretty much identical to his animated counterpart including that late 2000s haircut. It appears that they tried their best to replicate set pieces and props from the animated film. They obviously didn't mess with Toothless's design in very obvious ways because he's so iconic that god knows that would've caused absolute chaos...etc.
But then you have characters who don't look a thing like their animated counterparts - not just regarding race but smaller details like hair color or their costumes - in a movie that already looks to be a direct remake of the animated film where other aspects of said animated film are being perfectly replicated (or at least they tried very hard to replicate them).
If they had decided to do something completely different with this live action adaptation and change up every character in some way, this would be a completely different conversation and frankly, none of it would matter but because they seem to be cherry-picking what is and is not a direct remake/replication from the animated film, suddenly the conversation needs to exist because if they're being so particular about Stoick and Hiccup and hell, even Tuffnut looks like a pretty accurate replication then you can't help but ask... well, then why isn't Fishlegs blonde? Why isn't Astrid blonde? Why is Snotlout dressed in bright fucking orange? Why didn't they cast actual identical twins?
They're picking and choosing and it's adding fuel to a fire that was completely avoidable if they'd just picked one side or the other. They could've gone the historical route, they could've said to hell with it and made it all completely different, or they could've made it exactly the same... instead, they've created this confusing mosh pit that frankly shouldn't even exist that is unfortunately going to spark this so-called nitpicking whether people like it or not because you cannot argue that hair color or costumes don't matter when so much of the rest of the film already looks identical to the animation.