His first two points ("moderation is likely to end up pissing off those who are moderated" and "content moderation is always going to rely on judgment calls") are true of all moderation and certainly HN. They have nothing to do with scale though.
His third point is more interesting: at scale, even 99.9% accuracy is going to leave hundreds of thousands of mistakes a day. No one will care about the 99.9% you got right, only the things you missed. Reporters will call public attention to these.
That's a good point and not widely understood. But he stops there. All that shows is that content moderation is impossible to do perfectly, which we already know because of points 1 and 2. More interesting would be the part he didn't write: given that a large number of misses is inevitable and reporters will call attention to them, what follows next? Probably that the public image will be that moderation sucks. That's rough, but it doesn't necessarily follow that content moderation is impossible to do well.