I have been FORCED to pay school taxes for decades to educate other peoples kids, money the teachers unions have extorted from me and taxpayers via strikes. You are taking a harsh social position saying poor families who don't make enough to owe any income tax should not be entitled to a child tax credit refund, I presume your position is one of fairness. Well okay then why is the teachers union entitled to 10's of thousands of dollars of MY money when I don't have any kids? Why am I forced to educate other peoples kids? They chose to have kids, I chose not to yet I'm stuck paying THEIR bills.
If you are going to take a harsh position on the child tax credit for poor families, you can't have it both ways. People should pay for their own damn kids education, I shouldn't have to pay for it. No less harsh a position than you are taking.