The comment was claiming that Justin claimed that education didn't matter. I was clarifying that his point seems to me to be that the prestige of the institution you attend doesn't matter, and that more prestigious universities do not offer correspondingly better educations.
Now, as to the truth of that matter, it's a topic there's not a lot of good evidence on.
Obviously MIT and Yale and CMU all select from the very best students, so their graduates are correspondingly better than average as well. The question is whether they are more-better after attending prestigious schools.
Anecdotally, my friends who went to state schools got educations every bit as good as mine, in terms of the quality of instruction and rigor of the classes. Ditto for me comparing my CS degree to a MIT degree (I don't know about CMU).
Also, the null hypothesis (or the dominant prior if you're bayesian) should be that schools provide equivalent educations unless you have some reason to believe that's not the case. What evidence do you have that MIT and CMU provide better educations than other schools?
Again, note that the claim is not "You don't learn anything in college", the claim is "You don't learn anything more at prestigious schools".