If you go further down this line of argumentation you will end up at what will be cheaper capital punishment or prison for life.
Doesn't stop them from leading a gang over the phone, but that's better than recruiting new members in prison who are probably more violent than someone off the street.
2. Who gets them their immigrant visa?
3. Where do they live while waiting for it?
4. You do realize most countries require immigrant visa applicants not to be convicted felons in their home country?