If he was just sending junk e-mails, there'd be no reason to convict him. Though he probably broke some other laws. For instance, he probably didn't have an opt-out for people who received his spam - CANSPAM requires this. And, clearly he was making fraudulent claims:
Since the routing info was untraceable, the people who made purchases most likely never received their product(which most likely did not exist in the first place) and couldn't get into contact with this guy. So, there's nothing wrong with jailing this guy, because he's a crook.
My suggestion is that you actually read the article before you make judgement - it's short, so it's not like it'll take you a long time to do so.