gambling is not wrong on its own, you can use it the wrong way.
and although it can be addictive and lead to destruction of you and your finances but it is not happening to everybody and there are a lot of people who are just gambling for fun.
if you gamble just want to just have fun or just want to know it's not a problem, but if you're addicted to gambling I think it is not wrong, but iniquity itself
For me gambling is wrong because its a sins in our religion.. also not only gambling can give more entertainment.you can try other activity such as play dota 2 or league of legends.. their are many ways to find entertaining not only in gambling sites. or casino..