When you take a look at new questions you see that around 20% of the new questions come from new users. I think this is a little bit high. Are there any statistics that point out the reason for this? Is it possible that some of these new users are established users who feel hesitant or afraid of asking a question? Or are they people who create a new account for every question they make because they be afraid of Stack Overflow's culture?
Yes, the high influx of new users is a direct and deliberate result of Stack Overflow's culture. This culture:
- edits questions until they are readable and answerable
- removes chit chat, followup, and non answers from the answer area
- votes good answers up and bad answers down
- edits answers to make them more readable
- kills spam and off topic material on sight
- answers questions remarkably quickly
As a result, if you want to ask a question to solve your problem, this is where you come. Since you need an account on SO to ask, you become a new user.
(You seem to also have another slightly different question lurking in there: something like "do the mean nasty people on SO scare a bunch of established users into pretending to be new users?" but I can't see what an established user would gain by pretending to be new, nor why that would be bad for the site, nor what you think could stop that not-necessarily-bad-thing from happening, so I'm just going to answer your title question as written. It's pretty clear you disapprove of the SO culture but again, I can't see why you do and you're resisting when people ask you to elaborate, which is a shame.)
Isn't it only natural that most questions come from new users? Most people come here when they have a question. Many might have only one. So after they get their question answered, they are never seen again. Old users on the other hand get more experienced first to search for existing answers and might have in general less questions. With all those possible effects, I think it is very hard to get a meaningful statistic to your question.