because the rules as written suggest pretty strongly that a third level ritual spell is on par with or better than a 5th or 7th level spell & it causes many arguments. His statement is great & all when talking about a wooden or stone wall but is completely inapplicable for all the reasons you point out to the absurd wording of tiny hut but will be used to tenuously fill in for the long overdue errataThere's a logic problem here, alright. But it's not Crawford's. None of the spells you're quoting are everyday things - walls, gravity, bread, laughter - that we have experience with. Hence, his statement is really touching those spells at all. Why would you expect it to?
the decision from the 5e team to stop differentiating (Ma)gical/(Ex)trorinary/(Su)pernatural/(Sp)ell-like was a big mistake that causes a lot of problems with things like that dragonbreath & othersSo, back before sage advice. Many people were sure breath attacks counted as magical. It's common sense, it's surely not natural to have a creature barf up cold so it should count as magical. Except it doesn't.
The arrows weren't really the point, but for the record, you aren't burning anything with fire arrows. They're usually too fast and the wind kills the flames, too front heavy to be effective projectiles, or they people next to it will just stamp the fire down.
And this matters when? In an anti-magic field? I can't think of another situation where it would, off the top of my head. Except that 5e does distinguish between spells and other effects that are usually considered magical. And parsing the difference between various supernatural abilities is a far cry from realizing that a wall provides cover from most effects and attacks.
And what was the point? The point I was making is that 5e's rulings not rules goes a long way to expediting the game without having to provide a physics manual on how each thing works. We can still have arguments about how effective fire arrows are/were/should be in game, we just don't have an arbitrary rule bloating the books about it.