I don't use the perl irc channels, I don't know any of the people involved. The response below is purely based on the bpo post and the data you've provided.
"I did not find ridicule, not even a heated discussion."
I don't see it either. The blog post states:
By the vary nature, anyone posting in #perl-help, needs help and I'd forgotten that certain people view this channel as a shooting ground where you pour ridicule on posters "who don't understand their problem" - of course they don't or why would they post on #perl-help.
Reading the conversation posted above I do see people suggest that there's either a data problem causing confusion, or pointing out that there are a bunch of reasons which make this situation more confusing, stating some of them and a strategy for debugging what's actually going on.
I do know from first hand experience that people who are have worked closely with a code base or product for a long time can take offence to suggestions that something isn't being done right. Angry responses of "I've been doing it this way for 20 years!", when pointing out a critical security problem. It happens. It's often hard to take a step back and see the situation through someone else's eyes.
I believe this is just a human thing, one of the complex problems unfortunately. So many contributing factors, perception differs, sometimes people have unrealistic expectations and read things that aren't there. Throw in language barriers, mood (people are often frustrated when asking for help). There's a whole mess of reasons contributing to misinterpretations. One thing I noticed when attending TPC last year in Glasgow, some people made complaints about being offended by some things, but let other arguably equally offensive things slide.