There might be some substance to his gripes (I doubt it), but his method of interacting with other humans sounds frightfully flawed.
And it's just more of the pompous assumption that somehow the actual mechanical writing of code is the hard part of this job. It's not. The hard part is business requirements, task management, figuring out what the next and right thing to do is. Very rarely is our job a simple matter of writing code, the actual programming is often only a small part and most people's productivity issues tend to boil down to handling and understanding ambiguity or conflict in the business requirements, or motivation around them, or dealing with piles of legacy crap that needs to be cleaned and managed before moving on... not the coding itself.
A bunch of junior or new hires get sent home to do remote work combined with a guy who admits he "yells in chat", yes that sounds like a disaster.
And honestly it wouldn't surprise me if that's where the whole thing was falling down, not the competence of the programmers he hired.