Yotta claimed to be functionally equivalent to having a normal interest-bearing account with an excellent interest rate, and using a small portion of the interest to buy some lottery tickets. Buying lottery tickets might be dumb, perhaps even shameful (although I disagree as long as it’s not to excess), but it by no means implies that you deserve to lose your savings.
Yotta’s funds were backed by the US government. The trouble is that the link between Yotta’s funds and Yotta’s customers’ funds was somewhat more tenuous than they implied.