It's fine though, if someone can't afford to loss any single cent in gambling, they shouldn't gamble in the first place, case closed.
You are talking just like the poor people, because to the rich this is an example of what sets the poor aside, why? The poor don't ever want to lose a penny, even when they make let's say 100 in a week they can't take risk with a penny, that's greediness too.
If every penny you earned matters so much to you then sorry to say you aren't going anywhere, people like you can't invest in stocks and start up projects because every penny matters so much to you.

It's an exception if the poor who earn $100 have many responsibility which make the $100 not enough to cover monthly bills. But if he still able to save $10 and in the long run he's consistent, then yeah it's greedy.
I agree people should risk something to get something, but don't apply this in gambling.