Seems the Trainer is delusional or only experiences life through TV or the movies. Don't know what part of the world he lives in, but he has a lot of learning to do. Size doesn't always matter when getting down mean and dirty. A simple lead pipe,or sap, with the skills to use one, can make a lot of things more than fair and balanced for a much smaller man. Jumping into a front double bicep pose will do nothing to save one's ass...truth be told.
Those little skinny Mexicans, with their social clubs (?) in the Firestone area, North Long Beach, ELA,North Broadway, the Valley, etc will be from Sinaloa, Guerrero, Chihuahus, etc. Usually most can be tied to drug cartels. These aren't your average American pocho's. They also tend to attack in packs, and may even chop up your body and use parts for taco meat.
If your a big stud and have a really, really, really mean look on your face,than may also consider packing a 9 when going into one of their clubs for a friendly beer. Saturday nights and Sunday mornings are the worse time to enter. And for God's sake, never eye their women.