I’ll start with the short answer: we aren’t.
Now for the longer answer.
Why is it presumed that if someone chooses to explain what they believe and why that they are smug? I say that I’m an atheist because I think it is tremendously important for other atheists to know that they aren’t the only one and that it is OK to conclude that there is no god. Is that smug?
Is the simple choice to stand up and be counted smug?
No, of course it isn’t.
Now if I go further and say that I believe all religions are equally wrong, have I crossed over into smug territory? Do I sound like I’m saying I’m better than all those religions because I’m so sure I know everything about god (or the non-existence of god)?
Well, no. But I expect I need to go into more detail.