Because it's not just jealous weirdos that're sick and tired of his weird, featureless expression dominating YouTube, it's the man himself who repeatedly admits that he is essentially a kind of advertising-friendly sludge.
Edit: I'm so sorry. I had no idea the thumbnail was going to be that. He's a fucking monster.
This line in particular makes me feel crazy. He's so close to getting it, but yet going in the complete opposite direction. Maybe being genuinely yourself is something you should do BECAUSE of the risk - because it makes things valuable and helps you find people you get along with...?
Being your authentic self is good for hanging out with others, or going on a date, when the risk of being vulnerable is limited to yourself or, at worst, making an evening awkward. He's not looking to meet people he gets along with. He's running a business, and hinging success on being universally likeable is a dangerous gambit.
Now, we can argue that YouTube shouldn't be a business, but making your personality your business is pretty much a direct road to feeling bad and burning out. Your ability to eat, to get medicine, to go meet people is now directly related to your authentic self. When you inevitably start to feel burnout, you have to wonder where your livelihood is going to come from. Lots of people grind themselves to dust trying to be authentic.
Now multiply that by the people you employ. Now being your authentic self and being likeable is directly responsible for employees and their health benefits and their kids going to college. It all collapses if you want to stop being you or if that you becomes less likeable for any reason. Getting older and lower energy is suddenly a threat to several livelihoods. If we were talking about not being authentic on a date because it's risky it'd be stupid, but that's not what's happening.
Making the value of your videos something other than your "authentic self" makes it easier to take breaks when needed, gives more space for others to grow, and lets projects survive you. It's easier for others to take ownership of it and explore.
We wouldn't ask an employee to be authentic in almost any industry. YouTube, for better and for worse, is an industry.
Personality is important and huge, but you want to be REALLY careful about making your authentic one a product.