The article says that the man is prohibited from owning firearms, so he probably has a felony or something. I'm not sure about California, but you wouldn't need any kind of special license to own all of those guns and ammo in a lot of states.
Machine guns are illegal unless you have a... Class 3 permit? It's a hassle so nobody does it.
The qty of ammo isn't illegal but really really above normal. The assault rifles are more of a buzzword unless they are burst or full auto, in which case would be illegal.
Most states don't require licensure at all. You complete a background check at time of purchase as required by federal law, and if you aren't a felon or prohibited for other reasons, you proceed with the purchase.
Yup it's totally fucked up. After I picked out my handgun it took 15 minutes after that to complete my purchase. Ordered my food right after they started the background check cause I thought it might take a while. Got my firearm and my food was still hot when I got back.
There really needs to be more before being able to buy a firearm. At the VERY least training and safety courses. This is where my opinion gets considered controversial, but if we had a better health care system I think annual mental health checkups for gun owners should be a thing.
Because they are illigal immigrants, cant own a gun if you are not a legal resident sooooooooo the question is not why did he have guns but why was he here?