I'm not sure that some here get the simple economics of the issue:

If public schools are made "free," as Clinton wants, then why would low income students bother attending private Catholic schools?

Well, they wouldn't bother.  They'd be foolish to bother trying to get grants and loans to attend the private Catholic schools, when they'd need no such assistance at the public schools.

So the reason seems obvious to me:  What Hillary is proposing would deeply cut into the number  of applications to Catholic colleges.

Moreover,  this can be rightly be seen as an assault on private religious education.   

If I understand them correctly, some here are saying that these educators should just be pleased that students are getting a free education at public schools.  Huh?  Apply the same logic to whatever business you happen to be in and see how that shoe fits -- if your competitor gets a gov deal for give away your product for  free....how long would you expect to stay in business?