This may indeed be true, but Haskell has nonetheless developed a reputation, and it's not a reputation that it shares with just any other community. The only comparison I can think of is Lisp in the '90s and early 2000's.

My suspicion is this: There are lots of ways to make people feel inferior, or at least make them feel like you think they're superior. Most of them are ones that people probably don't do on purpose. But when you do it, the person you do it to is going to think you're a smug jerk nonetheless. There are also a lot of people who are supremely self-confident and therefore largely immune to being made to feel inferior. Many of them have been like this all their lives, and are therefore oblivious to this social subtlety.

One easy social gaffe that doesn't get discussed much is having no sense of humility about your language's obtuse syntax. Yes, I know, it's a familiarity issue, all languages have obtuse syntax, etc. etc. Doesn't matter. What matters is, if your language's syntax is different enough from Java's or Pascal's then it's going to be widely perceived as being obtuse. And responding to that with anything along the lines of, "Huh, makes perfect sense to me," risks coming across as a smug jerk.

Using the M-word is another famously risky behavior. Ironically, at least in my experience using it is also actively harmful to any attempts to explain the underlying concept, because at this point that word is @$#@ loaded. You can take someone who is already implicitly comfortable with the concept and uses them all the time in practice, and reduce them to a confused heap just by mentioning the M-word. And at that point, any attempt to pursue your goals will also risk coming across as a smug jerk. No, trying to address this issue head-on by writing blog posts with titles like "You already understand. . ." does not help. It just makes you come across as a condescending smug jerk.