The confusion is somewhat reasonable given that many synthesizers (including straightforwardly subtractive ones) have an FM knob somewhere. It can produce some really great metallic and/or bell-like sounds.
A synthesizer in which FM is the main way of making sounds, though, is extremely difficult to work with, since you're basically just modulating sine waves with one another. Even some very famous electronic musicians will admit to not quite understanding how to work with them in a predictable manner. The DX7, certainly, left plenty of musicians totally flummoxed.
My misinformation on the subject was in great need of your help, and I sincerely thank you for the facts.
No wonder I had to keep ignoring the nagging feeling that I should double-check my info about those synths.