They're using radios in a tactical scenario against magic opposition.
Despite Wright being well aware of how electronic surveillance fails around magic.
They're sacrifices.
Yeah, but them being the FBI's equivalent of class D personnel wouldn't change the fact that their organization made up and routinely uses the terminology they're working with.
I get why they did it on one level, but it's still a bit like going "Lasers are such a sci-fi thing, don't be such a geek. Now CLRs, that is Coherent Light Rays for you laymen, those are serious business". While talking to an optical engineer.
On a more direct note, I'm not sure they are deliberate sacrifices. We don't know exactly how long they've been at this or what their experience had been like.
I mean, they arrested a wizard in his own home, despite having had a bad experience once before. I somehow doubt it was with a real wizard, because pissing one off at home isn't something a sane person does.
If they're used to working with minor talents they could be familiar with tech bane, but only in how it effects more complicated electronics when exposed to them directly at short range. People with the sort of tech bane necessary to screw up guns accidentally are rare, even among wizards.
As easy as Dresden says weaponizing it is, I don't think we ever see it used by small time practitioners. It might be one of those things where turning around the inherent disadvantage to an ability takes power or insight that you don't have until you've been using it for a while.
They could easily be expecting that radios will work right up until they're engaged, and that a back up set in a sealed pouch or something will be just as safe as Molly's cellphone was while in her pocket while hanging out with Dresden.
This whole thing is still stupid of them, but it could be a result of the resource constraints of illegally operating outside of their mandate and a lack of relevant organizational experience.