What we are seeing is the wuss-ification of football. Started in the NFL with QBs, based on protecting offenses and maximizing points scored. Now it is at the NFL and college level, and is being promoted as player safety, but it is really risk mitigation based on potential litigation.
One one side, many believe the Clowney hit should be illegal as it "looked dangerous." On the other side, many believe it was a legal hit that impacted the chest first, then Clowney's helmet slid up to knock the helmet off the Michigan RB. Some refs this year will view it as the former, other refs will view it as the latter. Which is why I hate this rule, because it will be a judgment call. Teams always get screwed sooner or later when it is left up to the ref's judgment.