The thief excuse is that he doesn't have money, and when he needed help nobody have helped him, so he became angry and rebel against everyone who has a better life quality. Or he isn't in real need for money, but he thinks to be too smart and feel good by cheating others, showing how he is smart while all the rest are complete fools, wasting money on scam schemes! Basically the thief/scammer is someone who wants to have success by looting, draining other's sucess.
I won't say he isn't right. He had some reasons for doing it and believed there will always be fools to give him free money from what they have. They are fools indeed. However, some people stupidly gets fooled twice and that is what surprises me.
Some of these guys do not have conscience apparently and are ready to play on the intelligence of people, but I believe if everyone is smart enough to get to work and stop looking for free money, these scammers would have gotten frustrated and get to find better work too.