Putting that aside, it's fairly obvious given the human taboos concerning disease that if you have a mechanism for flagging a person as non-compliant with a health policy, that person is effectively tagged as diseased by implication. This is a convenient way to unperson members of a political class who are non-compliant with the policy (e.g., for personal/political/scientific/ethical/religious reasons). You needn't eliminate the enemy when their opposition to your power is embodied in their non-compliance. You merely need to make them compliant to eliminate their opposition.
However the comparison to TSA is not apt. TSA threat model is: One "terrorist" (though I'd call them "premeditated mass murderers") executing its plan is the total failure. For the vaccine requirements, the threat model is much different. Even if you just don't bother with any of this stuff on %5 of flights, it will still have a great impact in reducing the frequency of aerospace super-spreader events.
Sars-CoV-2 infects a lot of people every day, whereas there are many, many days in a row where no terrorists bother to board a domestic flight.
[0] https://www.aclu.org/press-releases/michigan-father-wrongly-...
How do you see digital health passports as having infinitely more possibility for govt mischief? Right now TSA has the ability to treat you like a criminal if they think you looked at them funny.
The health passport "mischief" seems more along the lines of "you don't have vaccine X, so you can't board the plane." While potentially problematic, that's kind of the end of it. It becomes a no-fly list, but one where you can actually control your status on it.