It isn't ethically unsound. It's a commons/coordination problem. What is the optimal strategy in infinite-round prisoners dilemma with randomized opponents? The randomization effectively makes it an infinite series of one-round prisoners dilemma. So the best strategy is always to defect.
The only way you can change this is very high social trust, and all of society condemning anyone who ever defects.
The only way you can change this is very high social trust, and all of society condemning anyone who ever defects.