I don't think there's much else to the question of the nature of belief.
I understand your point of view, as someone of faith. For you, the question is indeed a little circular. For you, God exists, and so belief follows naturally.
Tangle of course, is coming at it from a non-believer's angle, and from that perspective, the question is much more interesting - why do so many people turn to scientifically unevidenced beliefs, of such variety - and (for me) why is it that they care so much about other people's beliefs that they can get downright hostile towards them - even kill them for having a different belief. I think it's deeper than a simple manifestation of tribalism - I think that there are aspects of belief of such comfort in a harsh, ephemeral and potentially meaningless existence, that a belief system can be vitally important in allowing people to cope with life. So vital, in fact, that they can be prepared to kill someone if they don't share that belief system - they can't accept any threat to it.
As I say, I know that you have a different perspective Faith - but if you're able to accept (temporarily and purely as an artificial premise for the sake of argument) that beliefs originate from people's own minds, then the question of why is an interesting and quite wide ranging one.
Could there be any greater conceit, than for someone to believe that the universe has to be simple enough for them to be able to understand it ?