My only interactions with ljharb have been in TC39. More often than not when looking at issues he's active in, I find myself wanting a level of maturity and thoughtfulness that just isn't there.
His contributions are neither novel or very compelling. He's more of an open-source bureaucrat than an engineer or a developer, yet he is currently steering several major TC39 proposals. I've seen him shutdown or sidetrack valid input and criticisms in all of them. The vibes I get from his behavior are akin to him being a member of "the cool kid club" -- wanting to maintain that ingroup/outgroup boundary very tightly.
He really should just get out of the standards/committee space entirely for the time being, and get some coaching on leadership skills before reentering. I realize this is super negative. Still on the ropes whether or not this feedback belongs in the public space.