I've read books about how the innate survival drives within the brain from birth to infancy demanding the formation of attachments to guarantee survival develop into an attachment style (secure, ambivalent, avoidant) which then influence the capacity to develop what philosophers and psychologists refer to as "theory of mind", essentially the ability to form judgements about what others may be thinking and anticipate behavioural. Success or failure at developing a good theory of mind can determine your attunement to others which pretty much determines your success or failure in life and happiness.
That's a lousy summation or synopsis of some pretty good recent psychological research, anyway, I've seen a lot of vindication or validation of this theory in practice, in life. Mainly work but I've encountered lots and lots of it online, in part I think this is because the internet can become a magnet for people who arent well synced to others and who wont or dont regularly comprehend feedback about themselves.
There's a stock of responses and behaviours which I could list and I'd bet others have their own lists too of behaviour I associate with this sort of "failure to launch" when I encounter it. Appeals to imaginary galleries of onlookers or others who are believed to be in agreement but never in evidence, repeated attempts at humour which fail but which are in turn perceived as just further evidence that "no one gets me", "no one gets my humour", "hey, that in itself means I'm cool", that's just mentioning two of the most frequent ones I encounter.
Perhaps its just trolling and no more comprehensive an explanation is required but I tend to think that with new tech like the internet taking on an increasingly significant role it might be important. At a time it'd be infrequent to meet someone else at work or everyday life who used the internet more than twice a week, now its not uncommon to meet people who check it at least once a day.
Some times it really bugs me when people are behaving like this or vomitting their feelings up all over the place, especially if its in a medium which it does not suit, such as reviews on Amazon or feedback spaces on Amazon. That's one of my pet peeves. On the other hand I encounter it quite a bit in all walks of life and it bothers me too, really fuels any misanthropic undercurrents I've got.