Question

Why did americans think they were so special

Answer 1

 The danger of generalizing is that you are lumping all people together and bashing them. 
I don't know where you are from (I'm sure it's not the US), but don't you think you are special because you are who you are and blessed to have been born where you live? 
It's become very popular to bash Americans and run them down. It only makes the person doing it look jealous and petty. 
There are many different types of people in every country. Some are loud, some are obnoxious, some are quiet, some are giving and charitable. It's impossible to make a blanket statement as you are doing and have it be correct. 
As far as charities go, most people I know give to both local and international charities. I don't know where you are getting your information. It's flawed and inflammatory.