No one's basing it on one situation. It's based on his body of work and ability to dominate at the highest level. Ask anyone who was at the Tilton game last year. RL is the real deal.
Highest level of high school means exactly zero in college. Coleman dominated at Tilton how did that work out for PC?
Here are the freshman SG's ranked higher than Ledo (per ESPN) and their current stats. Goodwin and Purvis are doing well but aren't the man. The other three are just decent so far.
Smart: 14, 8, 4, 2.7 on 33% and 13%
Harris: 15, 2, 1, 1 on 44% and 20%
Sulaimon: 8, 5, 5 on 26% and 50%
Goodwin: 15, 4, 3, on 46% and 67%
Purvis: 12, 2, 2 on 52% and 80%
Not saying Ledo isn't a very good talent, but claiming he would be some kind of savior without seeing him play a single college game is not realistic.