You forfeit your remaining eligibility when you enter the NBA draft from college but don't if you enter the NBA draft from Europe because the NCAA decided it is so. Given their rules, it makes sense that they are enforcing the rules in such a way, but that does not mean the rules are legal (or make any sense).
The NFL would rather the schools pay for the development when they're young. The three year rule is an NFL rule, not an NCAA school. Maurice Clarett tried to sue the NFL about the three year rule and lost, as the rule is collectively bargained by the NFL and the players' union.
You're telling me that a top player in a sport where the money, at least in theory, is mostly divvied up based on their "name, image, and likeness" is seeking attention?
I think it was a biproduct of attempting to set a salary cap for university payments to players. They did not want to just make the scholarship limit a roster limit, as doing so looks bad for the student athletes, so they needed to raise the number when they switched from scholarship limits to roster limits. Now they can say that the new rules actually allowed additional scholarships, so its good for players.