They consume services in far greater dollar amounts than the taxes they contribute. Don't play the damn percentage game either. If they make under $40,000 per year, they aren't paying any net income taxes. It is income taxes and property taxes that provide the general fund revenues from which education is funded.
BTW, while I was a California resident, I paid the max rate for state income tax AND 28% federal AND max rate for all social security and related taxes. My overall tax rate was far higher than any illegal alien and the total taxes confiscated are orders of magnitude more than they even earned in gross income.
You don't know this. No one does.