Darth Vader’s black protocol droid in the comics (which is canon) uses torture devices and such on people that Vader interrogates, he also has a variety of questionable tools and has a very sarcastic attitude. The idea does seem weird, but not all protocol droids have the same personality or meaning as C3P0
I guess C-3PO and TC-14 created my stable image of how a protocol droid is supposed to talks and behave. Yeah, I am admittedly not much of a SW guy outside of the movies I admit that.
Sorry.