The parts of the city that these raids occurred in are predominantly black, to the tune of 90% or more.
If they were going to target illegal alien gang members the Chicago PD would have to go further south into the Pilsen neighborhood. Western Suburbs of Cicero are also predominantly latino gangs and many of them would be here illegally. There are documented ties to latino gangs in Cicero with MS-113 and drug traffic.
Cicero is out of Chicago PD's jurisdiction and since Cicero is mostly latino run now, the chances of Cicero PD busting up the latino gangs is pretty small. That's going to require Federal intervention also to accomplish.
The bad guys are running the show in Chicago. These raids/busts are feel good moves to placate the ignorant public, in a few days their aldermen will have them all back on the street. Business as usual.