erm i think you'll find that it isn't just islam that labels people as "infidels" mate... and what about the delightful words the christians dreamt up like "heathens" ?
erm, in reply to the OP, i find this too ... but i think the thing is that you have to be respectful of peoples beliefs
i think a lot of them think religion is silly (and well lets face it my religion is weird as fuck if you don't actually practice and are from the outside looking in as it were, you're bound to see things that make you go "wtf lol!?!?!?!")
also, there are loads of religious nutters out there who have really dodgy views on an issue such as homosexuality, or the rights of women. i'm not saying for a moment that you're one of those people but they definitely do exist, and they are perhaps more vocal than someone who believes in g-d and is just "normal" since well to paraphrase one of the sayings in my prayer book the wicked man always wants to gain companions in wickedness since he's scared of the dark whereas the truly pious man doesn't give a shit who agrees with him because he is walking in the light ...
atheists who hold such views generally don't look to atheism to justify them because atheism is the absence of a belief, but they may look to something else for example "the family" or whatever, so perhaps their views aren't as obvious as those of a "religious" person, and they dont become linked to religion in quite the same way
but to be fair this is something i get annoyed with, a lot of people it seems deliberately misunderstand religion and there are some things on this website (and others), the things people say about g-d or whatever, that just make me go
sometimes ! it's all a bit like the playground ... mock everyone who's different to you ...
a lot of it is simply ignorance, or as other people have said the fear that every religious person will be like some of the ones theyve encountered before
to be fair though i think that sometimes they have a point ... i mean there are some people who refuse to recognise that all aspects of their own religion and the people that follow it are anything less than perfect ... and are totally closed minded
and of course you're going to get that with atheists too, like "atheism hasn't caused any wars" ffs ...
our culture, capitalism, the media etc also encourages us to denigrate religion, it's one of the main prejudices which are socially acceptable these days ... because something that encourages you to care more about spiritual things, and helping others, rather than the latest car or mobile phone or whatever, isn't going to help people make a profit (well not that sort of profit anyway
) and the whole "do not kill" thing gets a bit tricky, too ... when all they seem to be doing these days is to try and psych people up for another war ...
i wouldn't worry about it though
you're going to get chilled out people who don't believe in any kind of g-d and you're going to get people who are defensive and intolerant, it's just like in all walks of life ...