Many but not all gamblers are claiming they gamble for fun and pass time. I was just thinking. If it is the reason why people gamble then why not play online games? There is a lot of good and challenging onlne games wherein you can interact with other people online?
In my case I don't really play online RPG games, but with 5 vs5 strategy games like dota 2 yes I play with them. It is not wrong to play the games you want right whether it is gambling or not. The truth is I am playing currently with my friends, and sometimes skip for a moment to play some dice games.
I also think that it's not necessary to choose between MMO games and online gambling. I can find a time for both games depending on my mood.