Gambling is not wrong, till one getting addicted to it as well becoming more greedier upon winning few events. Also it is wrong when considered it an source for living rather than using it for fun with small earning as well loss.
I agree with you, gambling is just simply business and entertainment. The people who abused themselves for not using gambling in the right way is making themselves wrong with gambling. Because they are not knowing what is their priorities instead of more important things to cover up first, they are making gambling as their first love.