Regardless how the comment tries to work around it, cognitive deficit is in fact rude.

The sense of decorum we all ought to have in participating in HN is called out in https://news.ycombinator.com/newsguidelines.html. As an example, Be civil. Don't say things you wouldn't say in a face-to-face conversation. Avoid gratuitous negativity.

Well, I don't know if they're cognitive ones but you seem to have some deficits in 'knowing how to engage people on forums' and 'knowing what security by obscurity means'. The content of your post is that isn't rude is just inaccurate.