... why do atheists (9% of the population, maybe) think they have a monopoly on truth, or that they are so superior to the other 91% of people?
That's properly termed a converse accident. As there are some theists who think they are superior to atheists there are also some atheists who think themselves superior to theists. So what? Each is silly nonsensical thinking.
I'll just say again, that almost all the major positive world-changing events in history have been done by theists.
That's a perfect example of an unproven assertion. And, this is how you think?