In one case you're talking about something along the lines of a dress code, and asking everyone to do the exact same thing on private property. This is not uncommon and only requires a piece of fabric outside the body.
In the other you are not only mandating a medical decision, but also the transfer of information about your medical decision. And at the time, vaccines were not available to even all adults.
I strongly believe everybody should be vaccinated, and would support some sort of passport for voluntary events likes sports stadiums or concerts, but we can't have the grocery store telling grandma that she can't buy milk without showing her vaccine passport on the new iPhone. It starts getting into issues of discrimination in places of public accommodation, and legally that gets kind of hairy. I don't really agree with the decision on outlawing the passports, but I understand why it was made.