It would make sense for Mexico to require tests, not for USA. The rate of new cases is 4 times higher here.
Mexico: 14,395 new cases, 115 per million
USA: 151,107 new cases, 458 per million.
By total number of cases, Mexico is No 97 with 12,001 per million; USA is No 7 with 70,861.
By number of active cases, USA: 28,003 per million. Mexico: 1,938 per million.
So this is a typical bureaucratic knee-jerk response. They pretend to do something but actually shift the hardship on us but do nothing themselves.