Hell, half the time the Feds are the only ones I kinda trust in the in the Education game.
Oh, I completely agree with you that the Constitution doesn't say anything about the Federal government doing anything with education.
However, to me it feels like, if they were left to their own devices, half the counties in the US would be teaching creationism to the male, Caucasian, Protestant children of landholders, and telling everyone else to go pound sand. And another third would be too poor to teach their kids anything. I feel like the Feds, as bureaucratic and glacial as they are, are the only things keeping education sane in many of our communities.
I would agree that, yes, we _could_ let the free market take care of the issue: if people want to give their children a sub-standard education, they will be less competitive in the national and global markets, and they will be competed out of viability within a few generations. But I would imagine that the competitive process would result in a lot of suffering and economic "readjustment" in the community, stuff that I'm going to be on the hook for as a tax payer. Either now, to make them give their children an appropriate education, or later, to cover their unemployment claims and economic restructuring costs.
Yes, at the end of it, a lot of this comes down to the progressive "I know better than you how you need to do your things", but how do you stand by when someone is fouling it up so bad. And in a way that could be compared to child abuse.