He's making low value content/the culture of the company is horrible/he's a fraud/it's more luck than skill. The actual critiques are personalized to the content and, to one extent or another, valid, but the social purpose of the critiques is universal which is that I felt uncomfortable that reading this might mean I have to re-evaluate my worldview and I'm going to dive into the comment section and upvote all the people telling me actually, I don't have to do that.
I actually spent over an hour writing 750+ words of my takeaways reading this document and shared it privately with a few founder friends of mine and I briefly considered also posting to share with the community but I took a look at the comments and took a look at what I wrote and decided I didn't have the energy to face the endless onslaught of nitpicks and misunderstandings that are driven, at the end of the day, not by a genuine intellectual desire to reach an understanding, but by the need to prove emotionally that others are not taking this seriously so I don't have to either.
All I can do is be vague and say I think this was an enormously valuable piece of writing that is worth engaging seriously for what it is as it might change your worldview in several important ways.
But also my larger meta-point is that there's a now near ubiquitous "sour grapes" attitude that's pervaded HN that makes it an extremely unpleasant place to hold a conversation and people reading should be aware of this systematic bias when reading comments here.
In as far as this is a document that says 'do your best, give 110% 25/8, sacrifice everything for the company', most of what I'm seeing here is the same general approval that latter-day HN gives all impractical advice that a very young person might come up with. ('Just do gooderer, all the time!')
I don't think the change is that people now are now closed-minded, I think it's more that something like Mr Beast's PDF of peppy twenty-something bromides simply wouldn't have made the front page at all in 2014. This would be over on Digg with the other pop-Internet stories.
More broadly, given that the comment section appears around 60-70% positive for Mr Beast, I'm unsure what it is you're actually after. Would you prefer it be 100% positive? Wouldn't that be a huge loss for the intellectual diversity that this site has to offer? Aren't there other, better places for hive takes (e.g. Reddit)?
Respectfully, I think the takes you're taking issue with are precisely the remnants of the old, diverse HN, and the takes you're tacitly encouraging are the monoculture that's taken over the rest of the Internet.