The whole POINT of "zero tolerance" was to protect schools from charges of racism, by making the punishment be according to rigid rules. But that will not satisfy Holder. Even though his own FBI Uniform Crime Reports show that blacks commit 50% of homicides, he does not want black kids punished at a higher rate than white kids.
To this end, schools will be forced, under threat of lawsuit, to punish white kids for the slightest infraction, while only suspending black kids if they literally commit murder on school grounds.
You think that was the point of zero tolerance?
This is related, but I think the primary purpose was to remove the responsibility from the school authorities for making decisions about punishment for infractions.
Later, it morphed into a tool for making sure that there was “fair” punishment of kids that just don’t get into trouble by punishing them for Tylenol/Midol, having a knife in their lunch to cut an apple, making an art project involving military references, etc.