I have very limited experience with this, myself, as my birds are all raised together and exposed to everyone else from a young age until pulled out of the mixed flock for breeding, so I can't necessarily refute this, but Reuben was broody-raised in a Silkie-only flock before I took him in and...
I have never noticed any favor in my mixed flock boys toward hens of the same breed specifically. They do seem to have their tastes in women in my experience and will favor certain hens based on that, but they're not necessarily of the same breed.
For the record, my mixed flock boys are...