The key word here is “sometimes.” I agree that in extraordinary situations, there are mitigating circumstances that lessen or eliminate culpability altogether. However, these extraordinary circumstances hardly upset the normal laws of morality for the vast majority of us throughout our lives. Normally when this question is brought up, it is to justify the actions and mindset of those within our own society. For instance, many poor families who are having a difficult time in this economy may turn to stealing what they can’t afford, and I have personally known of individual cases of this in my own community. I also know that such actions can’t be easily excused or justified, because there are both charities and charitable people offering assistance year-round to those in need. I also know that a trip to the local Catholic Church would ensure that one is given proper care. Thus the entire moral question of whether it is licit for the needy poor to steal from the rich is, in our society, simply not applicable and fosters an unhealthy attitude.
Rather than asking what the exceptions are to the prohibition of stealing, it may be better to ask in what extraordinary and rare cases these exceptions would be allowed, and under what circumstances.