I just flew back to the USA from Cancun on 12/26. They had a sign that said, quite explicitly, that we should not take off shoes. How can they deny that this i

I just flew back to the USA from Cancun on 12/26. They had a sign that said, quite explicitly, that we should not take off shoes. How can they deny that this is security theater, when they're only reacting to the most recent threats, while older attack vectors just scroll off the regulations?