a. Less than 90% of Americans claim to believe in God (and even less actually do)
b. You're assuming everyone on Slashdot thinks God is a myth. Rather than just claiming, "God is a myth," tell us why he's a myth.
Who decides which degress has more value to society?
Examples of "We know how to spend your money better" (by the government or the college): Non-Merit Scholarships (ethnicity, income, etc), administration costs/Overhead, professor salaries, and federal student loans.
Creating a tax through contract on graduating students is bad enough, but what making people have to pay a tax through the government? Horrific. Colleges should individually decide whether to switch to this system. Students should also be allowed to make their own choice about which college (and so, which payment system) to go to. Let the market handle it. This would also take care of your concern about money an engineer is paying going to basket weaving students. Honestly, I think it would be great if the government retracted completely from the University system and allowed the private sector to handle everything. No federal intervention - less expense in total.
Also, quick note: this would be beneficial for buisiness owners. Just keep all your money in the company and don't pay your tax. Even if your company is extremely successful, just pay yourself 80k.