The libertarian argument is that the government shouldn't be in the business of dictating education. That should be a private enterprise.
How schools should be run and financed is IMHO way beyond this discussion. And is meaningless about whether evolution is science and creation is some sort of "theory."
I must confess that the education received at the Catholic high schools in our area FAR SURPASSES that received anyplace else in the state of Ohio.
Last time I looked, Catholics teach TTOE. Can someone definitively say otherwise (that is a true request for info, not sarcasm)
I also must confess that parents whose children have educational gaps get their best results from private firms such as Sylvan or from private tutors.
And MacDonald's is offering a new chicken sandwich, which has as much relevance as the quality of Sylvan or private tutors (which are probably very good).
Private education versus forced payment for education IS the issue that OP raised that you considered bizarre. That's the "blood-sucking parasite" part.
Evolution stands ONLY because it's forced on people in government schools. That's the thesis.
In a free market of school selection, it would not stand.
And Catholics do not believe anything that detracts from the fact of God's being the Creator of "heaven and earth." (The Apostle's Creed.)
They are forced by intrusive government requirements to include things in their curriculum that I'm sure they'd handle quite differently if they were fully free.
Just one Catholic high school in our large metropolitan area had more National Merit Scholars than all of the public high schools combined.