I don't understand why it would be reasonable to require that the phone have a backdoor which allows them to access the data if they have a warrant for that specifically, but not reasonable to require someone to give up the the password under contempt of court if they have a warrant for that specifically.
Not that I necessarily think either is reasonable, but I don't understand in what way the second would be worse?
I suppose if a person turned out to have not committed a crime, and there was a warrant against them, if they were required to give up their password, they might fail to remember it?
Is that risk worse or lesser than the risk of authorities being able to e.g. get data without a warrant via the backdoor?
I'm not really sure?