While I get that security certifications (and existing contracts with the right people!), the slowness of such laws ans disdain for prisoners, especially doing their law research, are big factors, I see a point that even prison admins shall consider. Besides big cuts in spending on capable clients, opening the ability for inmates to write whatever they want in a word processor as easily as it can be is a plus to the surveiliance. Authocracies of today don’t ban their own social medias because an illusion of privacy makes people snitch on themselves.
Same with russian ‘grandma phones’ with big buttons. Some researches found thst although they don’t provide any functionality besides basic phone\sms stuff, they do try to call their motherbase, sending all credentials and geoloc. IIRC there was no argument about them sending the content of smses and voicecalls, but it’s troubling as it is.
+ Russian as in sold there, they are chinese, sometimes with a local branding.