I have been on both sides of hiring decisions a lot. Here's what I can tell you: a developer who has a shit load of Perl experience will be more likely to get a

I have been on both sides of hiring decisions a lot. Here's what I can tell you: a developer who has a shit load of Perl experience will be more likely to get a job at a Python shop if they show flexibility in their choices. A Python developer who bashes Perl for being a shitty terrible language will not simply because having a bad attitude is a red flag. If you have only worked with PHP 4 for the past 20 years and have no plans to move off that language then yeah you will have a harder time. But getting defensive about it in an online discussion is a weird thing to do and honestly a red flag more than anything. The tools may define you as a professional (to some), but not as a person. Getting defensive is a personal thing. If you do it as a professional that's pretty bad. If you take professional discussions personally, in my experience you'll be very difficult as a coworker.