The ethics of exploiting stupidity
Genshin Impact is both the most generous and the most exploitative free-to-play game out there. On the one side it has no paywall, and doesn't constantly shove monetization into your face when you are playing. You can play a game that is comparable in size and quality to Breath of the Wild completely for free. If you spend any reasonable amount of money on the game, you will get more characters and thus options how to play, as well as better weapons, and faster access to some resources which you'd otherwise have to grind.
On the other hand, Genshin Impact offers you a just 0.6% chance of finding "a" 5-star character or weapon in a lootbox that costs about $1.50. So if you get obsessed and absolutely want to find a *specific* 5-star character or item, you can easily spend thousands of dollars before finding that. That sounds pretty evil. If you watch several of those videos, you'll note that each of these whales is looking for a *different* 5-star character, which shows you how much that is personal preference, and not really necessary for anything in the game.
Of course we have to assume that the reporting on these excessive spending is skewed: Much of it is done on Twitch or YouTube, where sensational behavior is rewarded by donations. For some more successful streamers, pulling a $2,000 stunt like that might actually earn them more money than what they just spent. We don't know how many "whales" there actually are in Genshin Impact, and how many of those are people who can actually easily afford that sort of spending behavior. But with millions of players, it is obvious that there must be some people who are spending more than they can afford, and the game clearly lets them do that.
In the end we need to debate in how far this is an evil ploy, or simply a reflection of the world of growing inequality in which we live in. A business model in which everything from free to thousands of dollars is possible works because there are people who can afford nothing, and others who can afford to spend thousands.