People act based on circumstance.
If there is a lot of food, people will lean towards sharing their food, and helping others - even anonymously in a truly "altruistic" sense.
If everyone is starving, people will lean towards violence and stealing.
Does this "expose the rotten core within us?", or is it just saying we have the capacity for both? If we were truly completely rotten we wouldn't share in either case.
The fact is that environment and circumstance are inexorably tied in with our behaviour - a fact that we seem to wish to see negatively, our ideal being a perfect person who operates with true altruism in all circumstances regardless of personal cost.
Throwing our hands up and saying "go look at yourself in the mirror" is missing the big picture in my view, which is that if you want a good behavioural outcome, the environment and context of the behaviour is one of the biggest factor, and is a big target to attempt to improve. If more people are operating in a positive environment, you get more positivity.
Personal accountability, yes, is a thing, but is quite a lot more difficult to instil and improve from within a smaller slice of the world, like an app, and is more of a greater societal concern or otherwise would require propagation of an ideal with a reach that is quite hard to achieve through your app.