Reddit had considerably more users when Sync was created- so smaller amount per person over larger user base would pay for the bill.
With Lemmy, user base isn’t there yet to create that same economies of scale - so to pay for the dev’s time - each person would need to pay a larger amount.
Because later on, if they were found to be actually innocent - the person rotting in jail can be released and compensated (to whatever extent false imprisonment can be compensated).
If they were executed, it's over. The injustice can't be remediated in any way.