Just a clarification...The rule does not say "pulled, pushed, and drug out of bounds by the defender." The rule is forced out by the defender. When running full speed, it doesn't take much to force somebody off the intended path. There was contact, absolutely no question of that. Depending on which video you view (and more specifically when it starts and the angle of viewing), the contact may not look like it altered Reilly's path, it may still be argued, but I can see where people would question it. There is one video, however, that, IMO, clearly shows Reilly's path is altered when contact by the MSU DB is initiated. To me, that undoubtedly qualifies as forced out of bounds. Reilly did not run out of bounds on his own, it was a direct result of the contact from the DB.
The rest of the play, I don't think is really debatable. Reilly re-established himself within the field of play and completed the catch resulting in a a TD.
It's a judgement call by an individual who presumably would have had the best view of the play. A better view than 90,000+ people in the stands, the millions of fans watching TV, and absolutely better view than those that never saw the play but just want to complain. My opinion is the Ref got it right. Most times, I am able to form an objective opinion regardless of which outcome is better for my team.