I grew up in a computing environment where everything was an acronym. Programming languages like COBOL, RPG, PL1. Heck everything was done on telex terminals, most times you didn't even have a choice of caps (everything was upper case). Project names were acronyms, software tools were acronyms, equipment names were acronyms, parts and services were acronyms. Nobody thought twice about what was caps and what was lower case and only a pin headed manager would be anal enough to get worked up over it.
When I started learning Perl it was just another acronym language. It even says so, right in the introduction: Practical Extraction and Report Language. I didn't think twice about it. I wrote PERL, I used PERL, I put PERL on my resume, I love PERL. Then one day I got a response back from a job I applied for. The reply was "If you're going to put Perl on your resume then at least spell it right. It's Perl not PERL". I mean geez, if you're that bent over the capitalization then don't even bother with a reply because there's no way in h... I'm going to work in that kind of environment.
So now I use Perl/perl instead of PERL and blend in with the crowd. Call me assimilated. I won't hold a grudge against anyone who calls it PERL, I don't think it's even worth pointing out. But I will hold a grudge against anyone who feels it's more important to get Perl/perl right than to actually learn the language.