>Is the case of stealing food not at all morally ambiguous to you?

It is not ambiguous in the least. To me part of being human is being able to ignore one's natural instincts and make one's own actions. If someone is stealing food either they are no better than an animal, so they should be locked up like one, or they are antisocial and want to commit malicious acts in which they should be punished.

>What about the case of a young mother stealing diapers she can't afford?

To me this clearly is also wrong. Either the father needs to be working more so they can afford them, or the mother should create them herself instead of resulting to stealing them. The age of the mother makes no difference as basic harmful behavior like stealing is taught and understood at a very young age.