For example, someone W (say, historic, like from the 1500's) holds position X because of claim Y (I hate ... because of ...).
What would you call someone A who puts "words in their mouth" (He didn't mean Y, he really meant Z). The issue is that X probably didn't mean Z because Z is an anachronistic/out-of-character for W, while Y actually fits W's weltanschauung. (And, say I'm an expert in this field and A is not at all, so I'm qualified to call him out). What should I say? A is a ...?