So let me get this straight:
Youtubers get mad because reddit and twitter have early spoilers for chapters and talk about it, okay, that makes sense.
But then they jump to somehow thinking it's okay to do it in their videos titles and thumbnails, just because a small fraction of the fanbase does it? i call bullshit.
What about all the Youtube fans who don't engage with twitter, reddit and worstgen? there are a bunch of them! they are most likely the superior number in fact, since Youtube is a way bigger platform. Anime onlies included.
Their only goal is to make money, and click baity titles and thumbnails gets more views, so i think they are just using this really shit argument to justify their greed focused actions.
Listen, be greedy, it's your job and you're making money out of it, there's nothing wrong with that.
The only problem is when you try to justify it, or even try to make it morally correct, with these really bad arguments.
Just own it.