I don't really know why people think that gambling is bad. Gambling is just a game with money.
The people who plays are the bad if they do something bad when they play it.
It is not even people are bad but money is the one bad. Most of the people will start gambling like thinking just a game but after playing some times than most of them thinks they can make easy money from gambling than the problem will start. So as long as people are not targeting money than gambling is good.