Nobody is arguing that Stanley is anywhere close to his ceiling, which is also why he might be a first-rounder. Stanley might want to bet on himself, that between January and August he can get strong enough to make it through a season. Also, his game is not based on power, so this might be less of a concern.
Greg Robinson going that high is not a warning against Stanley entering the draft, but a carrot. Robinson would not have made it far past the Rams, if they passed, because teams need LT and QB and there are so few of them.