It doesn't matter about intent. Contact to the head with the helmet is an automatic penalty.
Neither is worse. Both are blown calls. I agree that the offsides penalty was wrong. It took away North Carolina's chance to tie the game. By the same token, the targeting non-call took away Clemson's chance to maintain possession. North Carolina got a second chance for the onsides kick, which shouldn't have even happened due to the penalty.
There is no such thing as "agree to disagree." #42 from North Carolina made clear, I mean absolutely clear, contact with the helmet. As I just said, there is also no leeway for intent. Contact with the helmet is targeting. It doesn't matter if the contact was intentional or not.
I always think officiating is bad. I think officials in general are horrible. I think the replay rules are convoluted. That said, you can't complain about officials blowing one call, but excuse them from blowing another call. You are saying the officiating should improve, and the officials should get it right. Ok, well, if you really want to get it right, the correct ruling would have been a targeting penalty on North Carolina, with #42 being ejected, and Clemson being awarded possession of the ball 15 yards from the spot. If you say that the only problem on the play was the blown offsides call, then you aren't really interested in the officials actually getting the ruling correct.
Doesn't matter if the announcers mentioned it. The video is indisputable.