Some people forget what it was like when they were starting out. They find it difficult to remember when they learned what they know now because it feels like they've always known it, like it was and is second nature.
It doesn't help if they were able, either through circumstances, zeitgeist or sheer aptitude, to pick up a topic relatively easily right back when they did first learn it.
And so it can be difficult for such people (or at the very least, some of them) to see that anyone else might, for whatever reason, be having a hard time picking up the same thing in .
Combine that with toxic personality traits and you can end up with an embittered person unloading on you for not being able to do what they consider to be a simple thing.
These people are a percentage of a percentage of a percentage of everyone relevant, but they do make a heck of a lot of noise when they're unloading, and they often gravitate towards each other, so they seem like they make up more of a group than they really do when you finally run across them.
Note that at no point yet have I mentioned Linux. This is a human problem that affects all topics and activities.
If you want to get into the peculiarities of why it seems to be more common with technical communities, it might have something to do with the fact that people who don't feel particularly confident dealing with other people often chose to deal with something else instead.
Computers and other mechanical things offer stimulating complexity without any of that human nonsense.
This can lead to poor interpersonal skills perpetuating themselves or festering. And so you end up with a few of the aforementioned misanthropes trying to control what they know how to control and lashing out at everything, or everyone, else.
