It bothers me because it may lead to overexploitation and turning a great language(rust, being my absolute favorite at this very moment) into an abomination from the depths of hell. Similar to what we've seen with many languages over the years.

Library - yes, of course it matters what it's written in when I'm choosing it. Software - no, not really, as long as it does what it's supposed to do, C, C++, go, erlang, java, kotlin, python, julia, rust or brainfuck for all I care - sure, god speed.

> Are you bothered when somebody says "implemented in C 99"?

Ironically, I felt this was your strongest argument because I am bothered when someone says that... like, I am first bothered that someone thinks the language their tool is written in is a selling point, but then I am additionally bothered (even somewhat enraged) that anyone considers their project being written in C99 (and not at least C++, and even explicitly so) to be a selling point!

Like, whenever I see "implemented in C99" I tend to be able to very quickly find a few buffer overflows or memory leaks as it is so hard to dot all your eyes and cross all your tees manually in every single function (with the consequent annoyance that I say the code is likely buggy, get challenged to find a bug, find multiple sometimes only even a few minutes later, and then the goal posts shift to "well we fixed the bugs you found, so we're fine")... and so I guess "implemented in Rust" us at least telling me the code that implemented the tool I am about to use is more likely to be correct? ;P

Fair enough.

> so I guess "implemented in Rust" us at least telling me the code that implemented the tool I am about to use is more likely to be correct?

This was my point! It's information for potential consumers, that might or might not be interesting or relevant to you.

Also some people just like talking about how they did something, not just what they did. Maybe they're proud to show it off or they want to let people know about whatever cool thing they like.