So I understand that in some contexts it's important to specify that, for example, you've written a library for "Common Lisp" rather than just "Lisp". Here the original commenter is clearly just happy they can use a lisp for this task, and they got a snippy and slightly pedantic response that likely thousands of HNers are now reading.

So the top-level comment made me think "cool I should return to Lisp and hack something fun together" and the reply made me think "ah lispers can be tribal and petty towards newbies". It's fair enough if that's true - I don't know what value me individually doodling a few things can bring to a community overall.

You're being needlessly pedantic here - especially when, despite never having seen Janet before, I was immediately able to use it at a high level of fluency thanks to long prior experience with Elisp and CL.

It's not wrong to say that something written in a Lisp is written "in Lisp". It's less than maximally precise, but people who are interested in Lisp will understand that "which Lisp?" is a question of import here. People who are not yet interested in Lisp, on the other hand, could well see this sort of pettifogging by someone clearly invested in it as a reason to avoid becoming more so.

I think that'd be a shame, because learning to understand the concepts that underpin Lisps has informed my approach to my work, even in other languages, and just generally made me a better programmer; I think it's good for just about anyone to have that experience in some degree. So I think it's worth not representing the language family or the community around it in ways that make it less likely more people will decide to take an interest.

Besides, Lisp can be a lot of fun! As indeed it is here. So, y'know. Maybe it's worth being less concerned over how people talk about it, and more glad they find it worth the time to talk about at all.