It might be well to consider that the Amish do not eschew all medical technology.
So, while they are against vaccination, if ill or injured they will make use of medical treatment, including such high tech stuff as ambulances and kidney transplants.
So having access to a phone, even if it’s not in a home, may be justifiable for uses in emergencies (remember, a lot of them are farmers and farm accidents can be gruesome), as are ambulance rides. If the only way to save someone’s life is to have them airlifted to a hospital they aren’t going to object. Likewise, since the use of phones and pagers is standard in organ transplants, their use for a severely ill Amish awaiting transplant would probably be OK. So maybe some of the Amish using cellphones in a hospital setting have the OK because of the particular circumstances they’re in.
The other thing is the portability of cellphones - they aren’t locked to one person or one place and really could be used as a community resource. So, it wouldn’t be a phone for one person to yak to his English friends, it would be a tool for those who truly had a need to communicate with the outside world for a specific purpose - such as someone who needed to communicate with doctors in a different city about an ill or injured relative.
I’ve also heard that there’s a period of time for Amish teenages before they formally join the church and are baptized (the Amish were part of the “anabaptists” who did not practice child baptism, believing the decision to join the church had to be an adult one) when deviations from the strict rules are tolerated to a degree
I have a book of various essays published by and for the Amish - even THEY argue over the sense of some of their restrictions and periodically revise them. Each community sets it’s own rules, so the restrictions vary considerably from place to place, as already noted. But the Amish aren’t some museum diorama, either - they are a living culture, and by virtue of that, they do change over time. The Amish of 2003 are not the Amish of 1903 or 1803.
Perhaps if people didn’t see their rules as a rejection of technology but rather a refusal to adopt technology unless it worked in accordance with their culture this might lead to better understanding. They want technology that unites them as a community, not that divides them. They don’t view the new as automatically good. They want to know that a new gizmo will not disrupt their life before adopting it.