The order to target packages containing Ivermectin probably came from acting FDA Commissioner Janet Woodcock. She has attacked it recently, knowingly lying about it's effectiveness.
JANET WOODCOCK [9/21]: "That there are not data that show that ivermectin is effective, and there are data there is a rather large trial done in South America that really doesn't show an effective ivermectin or the progression of the disease…So I simply believe that ivermectin should not be prescribed either to outpatient or inpatient outside use in a trial setting, period."
https://www.webmd.com/coronavirus-in-context/video/janet-woodcock-kids-boosters-treatments