I am not sure what your argument is anymore? Everyone who attends these colleges is well aware of what they must pay, and it's a conscious choice they make. If you do not wish to attend pricey schools, apply for aid if you qualify or just look for cheaper options (there are plenty).
It would be beyond ideal if education was free for everyone but that can never be achieved, especially in the US. In the end, private colleges are businesses, and colleges like Bowdoin do a hell of a good job in providing their services. If you do not wish to attend it, no one is forcing you to. But these places do make it possible for students of low income to attend with their amazing financial services, I suggest you read my earlier post on the help I get from the college.
We have free K-12. College is theoretically no different.
I think the say is true for healthcare.
But yes, private colleges are really just businesses. With non-taxable status.