OK the HTTP is a UI. Seriously, these comment are trolling.
Please don't resort to accusing others of trolling, or of telling them they didn't read something (https://news.ycombinator.com/item?id=43677540). These are swipes, which the HN guidelines ask you to edit out of your posts here: https://news.ycombinator.com/newsguidelines.html.
If people are posting bad information or bad arguments, it's enough to respond with good information and good arguments. It's in your interests to do this too, because if you make them without swipes, your arguments will be more credible.
We have to draw some line on good faith vs bad faith arguments though. Not understanding the difference between a UI and API is a stretch and purposefully conflating them just to win a semantic argument is not productive.
The problem is that internet readers are far, far too prone to classify others as being in bad faith, so in practice, "drawing the line" usually amounts to a provocation. This bias is so strong that I don't think people can be persuaded to draw that line more accurately.
Moreover, the concept of good faith / bad faith refers to intent, and we can't know for sure what someone's intent was. So the whole idea of assessing someone else's good-faith level is doomed from the start.
Fortunately, there is a strategy that does work pretty well: assume good faith, and reply to bad information with correct information and bad arguments with better arguments. If the conversation stops being productive, then stop replying. Let the other person have the last word, if need be—it's no big deal, and in cases where they're particularly wrong, that last word is usually self-refuting.