There are a lot of legal reasons why online gambling is legal.
First of all, online casinos are not places where people gamble for real money, insteadthey are virtual websites where people take part in activities in the exact same manner as traditional tables and slots do. If the action is free, then so is the law.
This is why most online casinos are operated in precisely the same way as casinos offline.

With online gambling, though, you do not need to leave your home, so long as you have access to a computer. All you need is a computer, an internet connection and a credit card. You may put a simple bet on the slot machines and walk off, or keep winning and playing until you get rid of all your money.