Because of the rules used to bring it up for a vote, it needed 2/3 majority.
Fred Upton brought it up under a suspension of the rules because he knew there wasn’t a 2/3 majority. He never wanted this to pass.
Conservatives wanted to give the chairmanship to Barton because Upton is so liberal.
It’s funny that leftist bills always get 2/3rds to come up for a vote because the GOP didn’t want to be accused of being mean.