Why should he return? Let's even assume for the moment and for shits and giggles that the government would be honest for a change with its promises and even grant him full amnesty. Would you wanna come to a country where the media and even some of its officials spent the better part of the last decade telling every redneck that it would be a blessing for 'murrica if you were killed, preferably painfully? Where you can't even really rely on police and other legal forces to defend you if you were attacked by said rednecks?
That whole deal smells a bit like the GDR offering its fugitives to come back with no jail time waiting for them. A few were stupid enough to go. No, they were not jailed. But their life was made miserable as can be, from no job opportunities being offered to people not wanting to associate with them, fearing the same. And if you say that it cannot happen in the US, think McCarthy and his Commie list.
Or think of companies wanting government contracts, knowing that you're persona non grata.