First, gambles are same, it is wrong to single out Chinese. Take a guess how many Americans playing pokers! Just like majiang for Chinese.

Second, when gambling, the win or loss is relatively small compared to her total wealth. So even if against odd, the enjoyment from playing is exceeding the negative expected gain.

There's nothing irrational about this. If for your total wealth like your house, most will not bet against odds.

In summary, gamblers are rational, just like Chinese are rational. You haven't found a proper way to analyze yet.

As someone said "it is dangerous to do anthropology analysis on other.people from outside"