I think about sin there are no old or maybe new fashion or maybe mindset. Because it is already fixed and sin is a sin. Maybe what can we do is believe by ourself, i mean if we like gambling, just play and don't listen to other's comments. And for others, even it is a sin but disturb other people who want to do what they want to do is bad thing. As long it is not crime.
There's some contradicting principle when it comes to religion and the law of the land, but every citizen follow the law of the land as will be punish if we will not or break a law. Gambling could be illegal to some countries but in some countries it is not, so this means that every country has a different belief and it could be the religion that could affect the people who runs the government as they are the ones who are making the law. So here's a simple trick, if gambling is illegal in your country and you want to play, then transfer to another country that is gambling friendly and if your religion does not allow you to gamble, you always have a choice to change religion.
