Right or wrong are just a perspective. I believe that there is neither wrong nor right. They are just within our psychological state. Gambling is not wrong and it is not right. It is just how you can deal with it in the way you see fit. If you are in a loss of money, you should stop. If you won lots of money, keep playing. That's life. If you do not think about yourself, you will not survive.
There are many things here in this world where it was designed to be for good but can turn out to used sometimes for bad. Let's take a look at some example, guns - can be used for criminals but criminals can use it too for their criminal acts; money - can be used to buy good things in life as well as bad; food - needed for the body and nourishment but can be the source of obesity; and the list goes on and on.
So same is true with gambling, it was designed for entertainment but can also be devastating for players if loses very big money that he/she cannot afford to lose.