Actually, Robison argues that there was something rotten in continental European Freemasonry as far back as the 1790s; but at that point English and American Freemasonry was largely unaffected by the German/French innovations.
Robison demonstrates how far removed from its origins Freemasonry was in danger of becoming and what sort of political zealots were behind the changes.
History shows that the “innovators” and Illuminati of continental Europe won out in American Freemasonry during the 19th Century, as Robison essentially feared.
Robison was a Freemasonic Jeremiah: sympathetic to its fundamental ideals but extremely concerned for its future political impact in the hands of radicals and fanatics.
Proofs of a Conspiracy is hardly an endorsement of the branches of FM that have held sway in the US for more around 200 years. Yes, the Illuminati were infiltrators; but where is the originalist, ad fontes reform movement to reshape FM during the last 200 years?
That which we do not rebel against, when there are ample and justified reasons for rebellion and many years to have borne the ill effects, we are ultimately taken to have acquiesced to.
I’m not saying that FM is a cult or that it’s anything like the worst manifestation of the secret society phenomenon. Much Masonic activity is dull and tedious and a pitiable waste of time.
But I don’t believe you can use Robison to support your argument that Freemasonry is not answerable for its own infiltration, or for the continuing suspicion with which it is viewed by most non-Masons who have undertaken research of any depth.