This really is a must read. The following part of it is actually a reference to another source but is the clearest and most concise explanation of how SYG is a legalization of racism and race-based murder I've seen (emphasis mine):
Representative Hakeem Jeffries (D-N.Y.): “You’ve got a feeling of mistreatment, institutionalized in law, to perhaps legalize vigilanteeism, in some instances. That was the case with Zimmerman, hopefully it won’t be the case with Dunn….”
“What the law is doing in this particular instance is allowing for subjective bias perhaps to be elevated to be a legitimate defense. And that’s the problem.”
Chris Hayes: “And that is what’s so perverse. When people say … I honestly feared for my life, it’s possible you had completely erroneous racialized stereotypes of that person. and the honesty of your racial baggage shouldn’t be exculpatory. That’s what seems so perverse.”
Dr. James Petterson: “But it is and it has been, and the thing is we’re not going to be able to overcome the challenges in the criminal justice system unless we confront the pervasiveness of racial bias in our society.
There is a lot more to the article. It is titled "White rage and white lies: How the right’s language about race created Michael Dunn and George Zimmerman" and here is the link: