For example, the Roman Catholic joined together the First and Second Commandment to make the argument.
I would be interested in seeing the data that demonstrates that the doctrine came first, and that the division of the commandments came afterward and in response to the doctrine. Do you have a reference in Roman Catholic writings that I can research? That would be a nice thing to be able to show.

Of course, the Roman Catholic grouping of the first two commandments is also used by Jewish scholars, who take "I am the Lord your God ..." to be the first of the "Ten Words."
Guilt by association is not a fallacy if it is true.
On the contrary, it is a logical fallacy, and therefore not persuasive. Please see www.fallacyfiles.org/guiltbya.html.