I was listening to a Dan Carlin podcast where he summarized one king sending another king a letter that, as I recall, "called him a loser". I know Carlin is not a professional historian, but I was wondering whether colloquialisms like that are strictly avoided in academic contexts or whether there is ever a sense that they can summarize the emotional or cultural gist of something far better than a more neutral word might.
As you mentioned, Dan Carlin isn't a historian (as he frequently says) and his Hardcore History podcasts are mainly meant to serve as a sort of introduction to historical events or concepts to other non-historians. I think in those instances colloquialisms can be alright, as long as one makes clear that they just that - summarizations that are meant to carry over the feel of something rather than an actual accurate retelling of something.