Why Do Atheists Criticize People's Beliefs?

[Whateverist]

I don't criticize them for believing what they've been trained to believe, I'd just like to challenge them to salvage more room for critical thought by recognizing that neither they nor anyone else have conclusive grounds for belief in what cannot be demonstrated. It would also be nice if they'd use that capacity to reflect on the wisdom of fostering a secular society where everyone is free to believe what they like in such matters, but no one is imposed upon to live in the manner laid down in any of the holy books.