Some might argue that anybody who takes a position, has an opinion, or expresses their thinking.....is kind of stating their "belief".....as in....they're nailing their own colours to the mast on a certain topic. But religious belief, by its very nature, is an emotionally proactive exercise which requires private investiture for the person doing the "believing."
Those who don't feel any investiture, and see no reason whatsoever to declare any....are merely people without investiture.
You may love your wife and kids etc....but that doesn't mean everybody else has to, and others NOT loving your wife and kids in no way invalidates how YOU may feel about them.
When it comes to "god" however, there's this common notion (amongst believers) that everybody must take a position...(one way or the other) and that position is extremely revelatory about a person's thinking, their ethics, their morality etc....and a whole host of other "deductions" that their expressed position is supposed to reveal.
For those who state quite openly and honestly that they personally don't experience any kind of "otherworldly" connection, feeling, bond or relationship with an unseen personality and have no dialogue with it, either privately or in collective worship.....well that's hardly an assertive opinion is it?
That's usually just an individual who feels no investiture, and if truth be told.....may not even WANT to feel such investiture given that there's no rational or logical reason for them to feel that their lack of investiture even matters in the grand scheme of things.
Whereas it may puzzle "believers" why none-believers actually exist....it also puzzles none-believers why believers actually exist also.
I guess a fervent one-time-believer who claims to have outgrown their belief MAY have something to say on the subject because then you're dealing with somebody who has likely experienced both sides of the spectrum. At the end of the day however, belief is a very personal thing.....as is disbelief.
These are evaluations that each person must make for themselves.
Just as with politics, there are people who occupy strongly opinionated, polarised camps and who will likely have their own "sound" reasons why they feel their camp is the right one for them....and will perhaps wish that everybody could see things through the same lens as them.
Some people believe that the world could do with much more atheism, and would benefit as a result.
Some people believe that the world could do with many more devout, worshipful people...who've submitted themselves to the spirit of "god."
What's worse?
A socially conscientious atheist who strides to bring peace and harmony to his/her community?
Or a devout, hubristic believer who thinks that guns and bombs are his/her best way of advertising their "god" and his holy agenda?