I'd wager that the people who don't want 17 year olds having access to porn are probably the same ones who don't really want sex education, either, aside from the "On your wedding night, God will let you know what to do" speech.
Most porn is certainly made for commercial rather than educational purposes though and idealized stuff with giant penises and huge cumshots seems to be more commercially successful.
Effectively it's more about fantasy and than reality.
Then there are also the more extreme cases of family members renting prostitutes for young men, but I think that was much less common (though it still happens.)