I see religion as certainty of uncertainty. You can only rely on God. God only knows (with certainty). It's humbling. Too many religious people share that perspective to outright discard religion.

No strong, "true", deep religion makes people more suggestible. They have no direction, because they keep changing direction. It allows for "false" religions to lead people to do or suffer terrible things.

Many that fight "religious" wars weren't/aren't very religious. They are opportunists or victims of their own lack of direction and faith. They seek religion but mistake it for fixed, easy answers to life's struggles.

Those that are truly religious, as I see it, don't assume too much and feel stronger facing uncertainty or adversity.

Edit:
Religious vacuums are dangerous. It allows rackets like ISIS or Scientology to fill it.