Greg LOLing doesn't prove anything about Prop. 13. Nor does the bill not mentioning people explicitly by color.
The Serrano v. Priest decisions were a series of landmark California Supreme Court rulings in the 1970s and 1980s that declared the state's public school financing system unconstitutional. They ruled that relying on local property taxes created severe funding disparities based on district wealth, violating the equal protection guarantees of the California Constitution.
So people in the 1970s knew that funding public schools on local property taxes was wrong and would disproportionately affect non-white residents. Yet they created and voted for Prop. 13 anyway.