I'm not sure the two possible reactions you listed are the only two. If it's said in a reasonably polite way, I think clarirying the name for someone new to the language is fine. And if it's reasonably polite I don't think they'll be offended or think someone's "swallowed a stick" - I personally would take note of it but be more interested in seeing what their advice regarding my problem was.

I see the one of the purposes of this site as, in a very general way, helping people to use tool to solve problems. And part of learning to use a tool or how to solve certian problems is to learn the proper vocabulary. And while PERL, Perl, and perl won't ever get confused too horribly (no one will think you're taking about a different language entirely), it's still nice to know which to use when. And it can be a sort of Shibboleth as well, indicating to people how deep your knowledge of / involvement with the language and comminuty goes. While this isn't always accurate or a good thing (I'm sure there's people who are solid Perl programmers out there who use the wrong form for some reason or another) I'm sure some people will make judgements based on this, as illustrated by the poster above, so it's good to get on the same page as everybody else as far as nomenclature IMO.