It seems a shame that someone with a very treatable mental health problem should continue to suffer a limited life just because we're all too polite to say "have you thought about CBT?"
I do wonder what you'd say if someone described a physical health problem and people suggested they go see a physical health doctor.
You're making a series of assumptions here: that the problem can be accurately assessed this way, that the commenter is qualified to do so, that a message board comment is a suitable medium for such a message, and that the noise of this being an internet argument trope wouldn't drown out the signal of human concern. That's a lot of slack to cut "this guy has an anxiety disorder".
I'm sure you didn't mean it that way, but it's still something we all need to have the discipline and good taste to avoid. If we have to we'll add it to https://news.ycombinator.com/newsguidelines.html, but I'd rather avoid having a laundry list of verbotens.