Because often the offers are made and accepted when the person is underage and the collusion to keep there being no pay. If colleges didn't get involved at all until people were 18 and players were paid I wouldn't have an issue.
It is like the difference between a college student who meets and dates an older individual vs a college student who dates someone who knew and groomed them while they were still a child. Both may be legal, but far more people will be appalled at the second one.
This feels like post-hoc reasoning, given that the parents are involved, and that the person can also stop, transfer, whatever on their own later on.
> while they were still a child
Referring to 17-year-olds as 'children' is simply being disingenuous. You can join the army at 17.
The second statement in no way supports the first.
As for fame, which players get significant fame? Every team has over fifty guys on their roster - how many of those could ever be named by a random member of the public who isn't a diehard fan of that same team? The linemen are the ones that cop the brunt of the big hits - how many linemen ever get known by name?