Losing to Pitt did not keep us out of the playoff. Losing to Michigan did. In 2016, we had a close loss to Pitt, but won the conference. Clemson also had a close loss to Pitt, and won their conference, but went to the CFP.
What was the difference? Clemson had no other losses, while we suffered a 39 point beat down at Michigan. That was the "unforgivable loss" in the eyes of the committee.
The idea that Pitt kept us out, and not Michigan, is something they like to throw around on the Lair to make them feel better about themselves lol