There’s nothing inherently bad about green passes: they are a useful tool for limiting viral spread during an outbreak.
But mandating green passes is ethically acceptable only when the alternative is a stay-at-home order. This means that green passes may become obligatory only during a surge that threatens to overwhelm hospitals, and only for entering certain crowded areas. Of course, private businesses should be able to set any additional rules they like.
Anybody who wants to “save people from themselves” is endorsing enslavement. Restrictions should always be the minimum necessary to protect hospitals from overwhelm.
The European Green Pass was created by the EU government. Embracing it is dangerous, as is relying on the government for anything. A government that can give you everything you want is a government that can take away everything you have. Should green passes be required to access all public places, nasty leaders will be able to isolate dissidents and protesters, limit access to courts, constantly track whereabouts, force people to take a jab every month, and perhaps even automate the process of repression by adding social credit scores.
It’s always harder to regain freedom than to have it taken away.