Upvote:15
You are quite correct that the linguistics of the situation shows such association is nonsense.
The two writers in question appear to have both been primarily active in the 1800's. Obviously, the state of the art in Historical analysis has advanced some in the intervening 2 centuries.
In particular, it wasn't until the late 19th Century that Indo-European Linguistics really started to gain steam, and probably more like the early 20th when it became widely accepted. So the kind of linguistic analysis you and I rely on simply was not available to those gentlemen. They had to rely on other markers (like perhaps the two peoples' cultural behavior and geographic proximity, and yes perhaps even some eurocentric thinking), and clearly that led them to a wildly different conclusion.