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.
Risk alone may not be the only aspect that made gambling to be negatively viewed by many, why majority of people sees it that way is because of the impact of the loses in gambling such as debt and selling of personal property just to settle gambling loses, but also another feature that makes it more negative is the fact that, gambling get one addicted and as such since the outcome of addictions is heavier than that of loses, gambling if viewed from an addicts perspective it becomes a pour bad habits.
So the only time gambling will be considered as irresponsible act is when it obvious that all the mentioned elements are in place with the gamblers and he is obviously uncontrollable, but if one or two mentioned is absent or all mentioned negativity is absent it becomes a managed gambling habit's which can be call professional gambling.