Is being unwilling to accept criticism immature...
They are either immature or just being trolls, because no right minded normal person would be so bull headed to something that is in general, a tool that serves for the betterment in general...
If there was no criticism in the world, nobody would have stopped the death camps of Nazi Germany..nobody would have told the caveman building the square wheel to try making it circular...
we do however, live in the age of the Trolls, and they use criticism as a disguise to get a reaction...so it doesn't surprise me to know that a lot of young people today can't tell the difference.
Criticism should never be viewed as nothing more or nothing less than a fellow human being tapping you on the shoulder and making you aware of one or two things that aren't sitting right.
Now, as for the way criticism is delivered.... well, that's an entirely different matter. But i think it's just a sign of the times we live in...
Criticism which used to be an art form and an aid to the development of mankind and society, has been reduced to a ( like & dislike ) on social media networks....
All in all, at the end of the day, if someone is going to be touchy about other peoples opinions then perhaps some should think a little longer before opening their traps.