I think the reason people who are under 20 seconds display such immaturity and little compassion for anyone else is probably because of the average age of speedcubers. Teenagers and 20 year olds are still in the mentality of "let me show you how good I am and how much you suck", instead of "hey, let me share my wisdom with you". The mentality of a young person is if they are at 20 seconds, then anyone over 21 seconds sucks, if they are at 15, then anyone over 16 seconds sucks and so on.
I think actually right here you did a good enough job of showing how much you suck without anybody else saying so.
Just to make it clear however...
You seem to have forgotten that the majority of knowledge the speedcubing community has is based upon a bunch of 16-20 year olds in the early 1980s and a majority of the further advancements (i.e. improved algorithms, improved fingertricks, expansion of the community (thanks pjk), some BLD methods) have been made by yes, 16-20 year olds.
You've been to one small competition. Did you cube much with the people there at all? The idea that these 'teenagers and 20 year olds' don't care about sharing knowledge is ridiculous and it should take half an hour with 99% of them to realise how wrong you are. At least, that's my experience with every comp I've been to so far.
It's hilarious that you automatically assume that fast cubers 'must be nerds' and 'need to show their [social] dominance', clearly you talk to little/none of them. Sure it's a 'nerdy' hobby to get good at but it shouldn't take long in the community to realise that speed and levels of social problems do not correlate whatsoever.
There is little point being offended with this thread. In fairness to Dene, 'sub 20' used to be a bit of a holy grail and measuring that against nowadays standards makes sense.
In the most basic sense of looking at the 3x3 speed event only and deciding what is at all fast, then yes, anybody who is over 20s really "doesn't matter". It's just a fact of a competitive sport that people who are not (yet) in the top 5-10% of a region/the world are not 'important' because they aren't pushing any boundaries.
This isn't designed to 'put people down' or 'crush their aspirations' because fast people aren't good character models. If you want to be fast badly enough, then you'll just do it. What x,y,z says shouldn't come into the picture.
Also I checked the thread again before posting - what Dene said^