I agree with this.
One of my favorite tanks was a strikingly beautiful demasoni colony, of at least 3 generations in the same tank, and had "no" other species.
It had a large pile of rock work, surrounded by clumps of African Bolbbitus moss, and evolved between a population between 8 and 20 individuals, constantly breeding.
I don't find to demsoni to be great cichlid community spieces.
In nature in the Pembro rocks, a group of demasoni will stake out a territory of about 20 sq. ft
I especially don't believe demasoni belong with Mexican cichlids like salvini, or Amatitlania although they will tolerate the same water parameters.
They are not found in the same softer water parameters as jewel cichlids, so in my biotope mindset, they do not belong together, either.
I personally find mishmash cichlid communities especially those that don't inhabit the same water parameters or the same colonial habitats irritating to my eyes.