"and can use other technologies"
The fact that they are not using these technologies to stay in touch after choosing to eschew the primary technology demonstrates reality.
It's not my job to cater to every individual persons tech interests.
If you don't want to use Facebook, thats fine, but you cannot complain when you don't get the benefit of Facebook.
If you don't want to own a car, that's fine, but you cannot complain when you don't get the benefit of a car.
These are personal decisions here. Conformity is disliked but presents great benefit to social cohesion. If you're a nonconformist, you don't get to have your cake and eat it. You have to deal with negative side effects of non-conformity.
They're welcome to use secondary technologies to communicate and stay in touch, but in practice, it takes dramatically more effort and brain space to do this, and as a result, they do not accomplish their goal