Well, “Hun” is a derogatory term for a German, like the “N” word for a black. The appropriate use for the term “Hun” is as a reference to the Turkic (presumably) peoples from Central Asia who invaded the Roman Empire in the late Empire.
The British propaganda machine picked up on one unfortunate use of the term “Hun” by the Kaiser in WW1 when referring to his troops and how they should behave, blew it out of context, and used it a figure of speech to defame WW1 German troops.
Considering what the Brits had recently done in Ireland and were engaged in doing in India at the time, I think “Hun” would probably have been far more appropriate to employ in their case at the time.
Hun is certainly a derisive term.
It is used most often to describe that particular quality somewhat unique to those of Germanic descent - being most comfortable and content when following orders.