Thats false at least for me. I put some seeds from a Bonnie plant in a pot for fun and it worked. Sprouting out flowers now, I did this with a Thai birds eye btw.
Ive gotten Bonnie Mucho Nacho seeds to germinate and grow. I bought the plants last year at Lowes and saved seeds. Lack of space and other priorities prevented me from planting them
I'm going to be trying with my one Bonnie 'Havasu' that I rescued this year. Won't learn a thing till next year... unless I stick the seeds in the Aero Garden this fall. Might do that. It seems like a new breed, so what happens is anyone's guess.