Joe Ga took the Gulf Cartel quite seriously, as this group could have been as big as 'Goge Wu' level organization if it weren't for having the United States as a troublesome neighbor.
But the Gulf Cartel isn't doing badly now; they are Mexico's super drug trafficking organization, second only to the Sinaloa Group.
The biggest difference between them is that the Sinaloa Group controls most of Mexico's land routes, while the Gulf Cartel dominates the sea routes.
The Gulf Cartel basically has control over Southern California.
Monica's screw-ups dragged the Gulf Cartel down into trouble. It's quite normal for her stepson, who is 15 years her senior, to want to kill her, and arranging someone to watch her on the sea isn't surprising at all.
Actually, in Joe Ga's mind, it was a bit odd that the Gulf Cartel hadn't arranged mercenaries to bomb the area with RPGs.