For these deeds, one dude goes to jail and the other doesn't -- not because of sheer sampling (per minute, Gillis is a far worse offender) but because of profile. Drama is official DJ to the platinum-selling TI. He has a major-label record contract. He's rich. Gillis is this twenty-something former engineer who drives a Chevy Cavalier with a tape deck. The RIAA cracked down on Drama and not Gillis because Drama got too big for his britches.
The interesting thing is that he'd been using those britches to endear RIAA rappers to the streets they've deserted. Drama had entered into tacit agreements with major labels to put their rappers over his unlicensed beats and hawk them cheap in corner bodegas. He did this so well he's (rightly) credited with resurrecting Li'l Wayne's career.
People aren't blind to either the service these artists provide nor the way labels regard their art as pretty theivery, and it's pissing them off. Mixtape and mashup artists connect big labels to the grassroots, they market across genres and demographics, and they do so with very little outlay of money from the labels. Persecuting them is horrible business made worse because it's begun turning legitimate artists into felons. The good news is that Gillis will probably escape incarceration as long as he doesn't trade that Cavalier for an SL.