It's important to remember that he's not talking about writers in general, but specifically MFA students. MFA students are training to be the best of the best, and the bar is higher for students who choose to enter such training.

God forbid someone come to writing later in life.

He does note that there are exceptions, but an unfortunate fact of life is that a lot of skills do begin with childhood. Want to be a top-tier musician? Probably should have started the violin when you were a kid. Want to be a top-tier athlete? Probably should've started training as a kid. Want to be a top-tier writing? You probably needed to have developed a love affair with language and literature as a kid. You can come to these areas later in life and still be successful, but it's going to be a lot harder.

God forbid someone not have a primary education in which they've read the classics.

Classics are classics for a reason: They usually capture something about the human spirit, and they're usually examples of great writing. If you want to learn to consistently write better than anyone else (and that's what an MFA program is for), you'll probably need to read and enjoy at least some classics; if you hate them across the board, an MFA program might not be for you.

God forbid someone have a mental illness that keeps them from writing all the time, or work three jobs to support their family and not have time to read.

Without sugarcoating it: If that's the case, no, an MFA program is not for you. The point of an MFA program is to write all the time. MFA programs are very clear about this, and everyone entering one knows that they will be expected to write all the time. If you're not, you're wasting your time and money and a spot in the program. If you don't want to write all the time, there's nothing stopping you from just writing in your free time, but an MFA program is basically a job.