Iverson got a pass b/c he was Iverson and had already proven himself so he didn't need to go hard in practice (he won the scoring title the year prior to the rant). These kids have not proven themselves at the college level so they don't get that excuse to not go hard in practice (which it doesn't sound like effort is the issue).
Now one can argue that some people make plays in games and others don't but, again - I don't think Iverson is the right analogy here. Iverson would make sense as the analogy if WRs that were highly productive in games were not playing b/c less productive players were playing in their place b/c they practiced harder.
And none of the young WRs really made any standout plays in the limited action they did get (I realize the less time, the less opportunities). Restrepo did not inspire much confidence with his opportunities as a punt returner (yes, I get that is a different position, but he did show he was undisciplined at times there). Let's also not forget that young WRs often don't see earlier playing time and I am sure it was even tougher for them this year with no spring practice.