they are no different than anyone else doing those things for their own reasons

They are absolutely different, because in some major religions, devotion is rewarded or promised heavily in the afterlife, which creates a great incentive. These people are more likely to become radicalized or extremists, often going out of their way to impose their worldview on others through harassment, aggression, or influence. I’ll point to Mother Theresa, who inflicted so much pain on others when she thought she was doing good, often withholding pain medicine and other treatments. She said suffering is what God intended, and so she did… unto others.