This frustrates me to no end on Science Friday on NPR (which I assume is what you were referring to… not much science elsewhere on talk radio). They have fascinating, brilliant scientists on… answering the dumbest off-topic questions the public can get past the screeners.
The people who work on the show aren’t stupid, and do their homework ahead of time to understand at least what to ask. The show should be Ira Flatow, or perhaps guest interviewers who know more about certain fields, interviewing the scientists they have on Terry Gross style. Perhaps Ira Flatow’s role would be to cover the basic questions quickly at the beginning, instead of leaving those to the audience.
Since Science Friday arose as part of Talk of the Nation, perhaps now’s a good time to change the format since they ended production of Talk of the Nation but Science Friday continues.
To bring this to the main topic - as a scientist myself, I’d get little value from attempting to directly ask questions about a topic outside of my field without doing significant homework ahead of time. I honestly don’t understand why anybody would attempt this, either by calling in to Science Friday or by making a comment on a Popular Science article.
I would - and do - get a lot of value out of other people directly asking questions, whether they are someone also in that field, or are e.g. journalists (like Maggie here at BB) who have done the homework.