There is always a person or two at the bottom of every thread like this that loves to spew hate towards people that like to share interesting side-projects, usually in a "you are wasting your time because your project has no immediate value to ME, go spend it serving my interests instead" sort of way. Claiming to also be a tinkerer in your public bio on the same website is gross, and IMO fair game to point it out.

IIRC, site guidelines don't specifically say "no ad hominems," but it seems to be generally understood that "no ad hominems" is the correct interpretation of this guideline:

When disagreeing, please reply to the argument instead of calling names. "That is idiotic; 1 + 1 is 2, not 3" can be shortened to "1 + 1 is 2, not 3."

https://news.ycombinator.com/newsguidelines.html

Trying to start from common ground isn’t “ammunition” imho.

Although it depends on how it is phrased of course.

> I've never liked using people's bios - even if public on HN - as ammunition against their comments

I'm inclined to agree, but in the case of outright hypocrisy I think the point deserves to be made, because hypocrisy is literally the worst