How is it detrimental?
Just to start, I support free college, but..
Widespread higher education
could lead to us losing a lot of primary and secondary sector jobs; if you have a college education and a degree, why work on a production line? I'm not 100% sure the impact of that on our economy, whether those jobs will need to pay more or if we'll just have a bunch of under-employed people, I'm not sure. I'm not an economist.
It's funny, a lot of the republicans are talking about getting rid of immigrants and all, but they actually work all those primary and secondary jobs, jobs that
(white) Americans flat out just refuse to do. They're incredibly vital to our economy because they're willing to work on a production line or farm all day for minimum wage, because to many of them it's still much more opportunity than what they could get elsewhere. Meanwhile, "native" Americans just go work at a store or restaurant.