Not using Catholic schools? Have you read the Church documents on the issue? I never had, except for a few stray sentences here and there. This article reproduces excerpts from the relevant documents. I found it quite eye-opening. I knew the Church supported Catholic schools, but not to the extent indicated by these excerpts. The documents would appear to establish a fairly heavy presumption in favor of using Catholic schools (it doesn't say that, but when it refers to them as "irreplaceable" and important to forming the "whole man," it's obvious the Church places quite a premium on them).
I realize the issue of Catholic schools is rather inflammatory, and not just among the progressive set that, no matter what their religious affiliation, are secularist to the core when it comes to everything that matters in their personal lives. Many orthodox Catholics don't like parochial schools. A literary set I ran with said the schools almost killed their faith back in the 1960s through 1980s: liberal nuns or mean nuns made the Church horrible to them. Today, many Catholic schools are elitist. They offer a few scholarships to the poor, but for the mass of people, they are simply out-of-reach. And then there are the handful of homeschoolers, for whom no education outside the home is acceptable.
Catholics who decline to use Catholic education for those reasons--secularist/worldly approach, tuition problems, valuing home schooling--I understand. Catholics who decline for petty reasons--better sports programs, their friends go to public schools--puzzle me. Of course, most people make decisions based on an array of factors so it's never a good idea to condemn someone's choice.