I don't want to personally say whether the joke in the article is in good taste or not, and I don't want to assess whether programmers' egos are too fragile or sensitive. I don't think that's productive.
I do, however, want to emphasize that when read by a broader audience than just the community of Haskell programmers, due in part to Haskell's reputation, the joke lands as off-color, as the G*P comment demonstrates.
Oh, you can totally do that in a pretentious and insulting way. There's lots of "(someone) took over and amazed the crowd" style videos where it seems like the pro is inserting themselves into the situation to awe people in a very cringe way. The worst ones in that style are the videos of that one guy joining buskers to show off his boogie piano skills while they sometimes enjoy it and sometimes just look like they wait for him to leave. (can't find the channel, I blocked him)
How's that different to a humorous basketball/hockey/football dribbling demonstrated by a pro-player on a youtube video for their audience's awe and admiration? I bet no one is treating it as "pretentious" at those moments, in fact many of the younger folks regularly get inspired by this kind of performances to start in the sport.
These types of depreciating and other-party-blaming comments tend to come from ego-offended senior developers who're used to thinking that they can always pick a new programming language in 20 minutes or so, because all of them resemble their favourite flavour of $java (not really).