I believe that athiest will not ever entertain gambling because the time that you made your first step inside is that you are already believing that you are lucky or that you have something lucky. It can also go beyond like you will call any deity, god or saint that they say miraculous or can give you luck. I remember when I'm in a heat of a game and I just continue to mumble the name of the Lord.
That's just part of yourself which trying to hold to something even there's no real changes that will happen aside from luck that will permit you
to win over this gambling activities that you are inside, better to enjoy instead of trying to believe in something that never exist.