the reason why Gambling is considered bad by majority of people is because of all the risks and chances of loosing money involved in it. which I think are true. but in actually gambling is only bad if it is done too much. excessive of everything is bad for us. not just gambling.
That's the point, excessive gambling habits are the reason why most people consider gambling bad because they don't gamble but they see how gambling ruins the lives of many around them, they lose all their money, sell their properties, and do all sorts of things that they shouldn't be doing just because of gambling, and these things create a negative image for gambling in the eyes of a society where people are not very open-minded and see things very differently.
If people take gambling as a fun hobby and an entertaining activity, spending a limited amount of money and time on it just to pass the time or even to try their luck, gambling would never have a bad image in the world. You don't get ruined or lose everything you have if you gamble responsibly and not excessively.