If you don't mind, could you give some examples of what conditions interfere with what parts of that process, whilst preserving the capacity to otherwise engage productively on HN?

I think people with learning disabilities and people who do not understand the tone they are expressing over the internet can still contribute positively to conversations, they just need a little bit of grace.

Given the limitations described, what accommodations or "grace" do you propose?

I've already outlined that: clear expectations & when someone does something wrong, but otherwise seems to behave in good faith, explanations.