I think the big issue is that the statute prohibit judicial review of the secretaries decision, which means that the secretary doesn't have to follow prep at all, other than issuing a declaration, because no court can review it. That's a problem, because there is no protection where the secretary exercises his discretion maliciously or in violation of law. This is beyond chevron deference.
@GodsRiddles I'm in talks with several law firms to sue the federal, state, and local governments over current COVID-19 and seasonal flu drug mandates because those mandates require you to surrender your fundamental liberty interest to sue another person who injures you from the drug or its administration, which is an unconstitutional requirement. You can read why here: