I think very few are opposed to them going straight from high school, me included. The only ones "opposed" appear to be the NBA whose rule it is that they are not draft eligible until they are out of high school for a year. My qualm is with the farce of college in the one and done era, and essentially forcing guys who are draft ready to play a year of college as borderline fraudulent students. The NBA wins because they get another year of maturity and scouting, reducing their risk with the 18 year old draftees. I don't think there is a free pass from the public, perhaps from the media, though. The basketabll and football rules are a boon for the pros as it stands. The colleges, and yes, us as fans and ticket buyers frequently lose because of the diminished product on the floor and the growing challenge of developing teams and players over time.
If they are making a decision for college, they should make a decision for college. The three year rule in MLB strikes me as a reasonable compromise between the interests of the players, the colleges and the teams. Higher level draft choices in baseball are assuring an education if they sign by negotiating college expenses in their contracts. Basketball players should do that, too.