They don't understand. I myself had 16 years of Jesuit education, and 15 more years before I started teaching. There are oceanic depths to our faith, and you must learn as much as you can, so that God will use you as an effective channel of grace so you can communicate your faith to your offspring. Next, Catholic home schooling must be schooling. There must be organization, administration, a pattern, a schedule, and a program.
Somebody has to be in charge.
Mother and father must cooperate in the home schooling. Home schooling must be sacramental. In other words, the Church that Christ founded is the Church of the Seven Sacraments, especially the Sacraments of Eucharist and Confession. You, yourselves, should receive the sacraments of Holy Communion and Confession. Train your children to live a sacramental life.