There are some who, having never read Designed to Fail: Catholic Education in America, believe that I hate Catholic schools. It isn't true, of course. I only hate quasi-Catholic schools. Real Catholic schools are great... if you can find one.
But let's consider what it means to endorse a Catholic school.
What is the only thing a Catholic school, or any school for that matter, absolutely has to have in order to survive?
Clearly, the school has to have children. A school without children enrolled in its curricula will not long be in existence.
So, what is the only endorsement that really matters to a Catholic school?
Why, the endorsement Catholic parents make by conceiving children and placing them in said school!
Quite frankly, it matters not one whit whether any particular person says or thinks, whether he be lay or religious, secular or consecrated, priest or bishop.
Anyone can endorse a school with words, extol that school to the high heavens, make the very air about the school glow with the marvelous things that are said about it. None of that matters if no one enrolls a child.
And the only ones who can enroll children in a school are parents.
Now, the only way to become a parent is to throw out the condoms, flush the contraceptive pills, pitch the patches, roll away the rings, immolate the IUDs and conceive children to place in the school.
So, ultimately, the only endorsement that matters is the endorsement that encourages parents to do just that.
Anyone - lay person, priest or bishop - who spends a lot of time praising Catholic schools but doesn't spend any time teaching Catholic parents about the evil of contraception or teaching those same Catholic parents about the wonders of having children is not accomplishing anything substantive. Like the man described in St. James' epistle, he sees the poor, hungry beggar on the street, encourages him with a hearty "Stay warm, get something to eat!" but doesn't actually provide any food or clothes to the impoverished person and is thereby condemned.
Do you want to support Catholic schools? Convince your fellow Catholic parents to stop contracepting. Convince your fellows to stop aborting, to start learning their Faith at an adult level. It is parents who keep schools going, nothing and no one else.
If you need someone besides parents to keep the school going, then you don't understand how schools work and your schools will fail. Period.
I have spent my entire adult life warning and teaching Catholic adults about the evils of contraception and the wonders of having children. I have also spent no small amount of time explaining Catholic doctrine: that the title on a school is no indicator of its Catholicity.
If you claim to be a supporter of Catholic schools, then show me how you have worked to end contraception and abortion among Catholics. Show me what you know about what the Catholic Church actually says constitutes a Catholic school. If you haven't done that work, then you a clanging cymbal, a sounding gong, and you are wasting everyone's time, most especially your own.