Moses Mendelsohn might not have “officially” been reform; it might not have even existed before him. Some have even claimed he was Shomer Shabbos. But, he paved the way for the ruination of most of European Jewry. It’s like someone who unlocks the door and turns off the alarm system. So, when the house is vandalized, whose fault is it? The guy who turned off the alarm? He didn’t break in or steal anything. Yes, but he made it possible for OTHERS to do so. Mendelsohn bears responsibility for the destruction wrought by his followers.
Zahavasdad: thanks for the clarification regarding Felix vis a vis Richard.