I haven't heard that. Do you have a link or some way I can read that in context. It often helps to read these types of statements in context to get an idea of where they are coming from.
I assume the Steele Eggers are the ones from Meyer Hatchery. Since the recent popularity trend of chicken keeping various hatcheries have come out with sexy "special" chickens to take advantage of that trend. These may be crosses hat have been selectively bred to enhance certain characteristics or they may just be hybrid crosses, generally of hatchery quality chicken. From what I can tell, Steele Eggers are simply hybrids.
It's hard to tell what the parent breeds are. With the white skin you'd think they are partly Ameraucana for the blue egg gene but with top knots, muffs, and tufts (at least on some of them) you'd think there might be Auracana or maybe Legbar mixed in but they have yellow skin. There is no telling what else they might be mixed with.
From their size (hens 5 pounds) you'd think their parents are not all that big which ties in with Ameaucana, Araucana, and Legbar. But their egg production of 3 to 5 eggs per week implies that they are not crossed with the commercial egg laying hybrid. I don't suggest feeding a high protein content feed to the commercial egg laying hybrids as that can cause medical issues.
I don't know what that mix is but I don't see any red flags to stay away from either lower protein feeds or high protein feeds.
I do, but as you notice different people have different opinions on how they should be fed.
My suggestion is to contact Meyer and see what they say.