You’ve stated that they are not being asked to make a back door but from reading the open letter from Tim Cook and reading the court order itself, it does seem to be a back door. It may be a locked back door but they do get to attempt to lockpick this door as many times as they want without fear of the stuff behind the door burning down.
You may also think that it is safe in the hands of the FBI but say a hack ever occurs on the FBI in which this new IOS gets taken. It can then be used by hackers just like it was used by the FBI. It’s not about one phone, it’s about once a hacking tool is made, even for good, it cannot be retracted from the hands of hackers.
At the end of the day, people should sum up the facts themselves and be aware of all that can happen from this. Then they can make their own decision about it. Instead we have biased articles leading people to think in a certain way.