The problem, especially in america, is that atheists aren't really atheists, they are anti-christians.

They want nothing to do with christianity, and throw out everything that is even remotely christian. (you know, the Bible has a lot of good stories about morality and how to be a good person)

So, these people, throwing out the teachings of morality and without another moral grounding, they become quite solipsistic.

So, you have this person who is all about themselves (which is grating on people around them) and anti-christian. Thus, when they meet a christian, they will come off as quite hateful.

Now, you want to see some really hateful people?
Attack them on things they think they know about science.

"The world is flat"
Oh my Goddess, the hate that will fly.
How dare you question this thing that we all know is true, and...
"but, if the earth is a ball, how can we see something that should be over the curve of the earth?"
(and a fight ensues, and facts get disregarded)

So, attacking anyone's beliefs (even scientific beliefs) people get angry and defensive.

BTW, everything in the modern materialistic science books is wrong. EVERYTHING

So, when atheist say they believe in science, and everything you were taught is wrong, then you have a very weird belief.