Do you ever go to a movie? Out to dinner? etc. Gambling can be considered a form of entertainment when, like anything else, done in moderation. Which is why I said that whether or not its sin is between him and the Lord. Although its an "appearance" of evil. And even that is subjective. You don't do what causes one to stumble I guess.
I don't know...I think you've started down the steep side of a slippery slope of sin when it comes to that issue. It's like saying that it's okay to bow down and worship a tiki god because you're not really worshipping the tiki God, but you're worshipping Christ. Maybe or maybe not, but it looks bad. Physical actions mean things.
Gambling and what it brings is surely the playground of Satan. I don't think anyone would argue with that. The question is how long can one play on a dangerous playground without getting hurt or hurting another? It's inviting disaster.