To me using $100 to gamble is way too big to be considered as what one can risk . Though most people sees as small amount of money but there's certain amount of $100 you may loss and think is a small amount of money, but when it will get to point you will know that the amount of money you considered small turnup to be something huge after calculating the losses
Of course, of course it is like that, when I bet in a casino I don't even risk 10usd, even if I lose 5usd it hurts a lot, but since there are so many people in the world with different degrees of economic situations, for someone 100usd is nothing, even if I raise the bet up to x10, for me it is a lot of money that if I lose it I think I would not return to the casino for about 1 year, but According to each person's situation the situation varies, that is why each person has to bet the Amount of money they are willing to lose.
In essence, rich and poor have their own risks, just like you experienced about $100 being a lot of money. Thus, even if you have a background of being rich or poor, but when you spend that much money to bet and say it is big money,then it is also a big risk for you regardless of being poor or rich. Therefore, I do not agree if it is assumed that rich gamblers take a bigger risk because for me, it depends on the ability of each gambler as well as how much they can do to bet,then it will also be a risk for them.