Maybe not right now, but when shareholders start demanding action over NSFW subs or subs that discuss illegal activities or subs that discuss the evils of capitalism or subs that just aren’t profitable and those subs start getting shuttered, then they will.

If you’re not wanting to use JS then you’re reliant on the users browser supporting prefers-color-scheme (caniuse) or forcing them to reload the page.

True, but let’s not forget that Lemmy instances are hosted by ordinary people without the finances to employ high price legal teams. If they receive a threatening letter from (for example) Sony or Disney they still have to either acquiesce or find a lot of money very quickly to simply argue their case.