This seems to be the prevailing wisdom. However, I am a "what if I tried this type person". I have purchased adults and sub adults that have issues. Three to be exact. One of them I got because she had an attitude problem and I wanted something to keep me on my toes. The most I have been able to do with those three is make them manageable. They no longer try to take my nose off when I open the tubs. Given the opportunity, they will strike. In all three cases is seems to be a fear response.
In addition to these buttheads, I bred a couple that were bad eaters when I acquired them. So far no jerks or bad eaters in the offspring. The "queen of evil's" clutch has not hatched yet though. Those eggs are already receiving a lot of attention. When they pip, they will get even more. The first thing my babies see, smell and feel other then their own egg goo is me or in rare cases, my wife.
I have not really had any eating problems with my babies. It is becoming very rare that I feed live even for the first feed. I will only feed live to babies if I am in a hurry to get them out the door. Feeding live is easier though especially on the first go. About half of what I have produced will take a ft rat on the first go. The remaining will get a ft mouse and then are switched to rats. There are always a couple that seem to need an extra week or so to eat but they come around. Every one of the babies is handled for a short duration at least four times a week whether they are eating or not. The only time I have been tagged by one of my babies is at dinner time and that is because I am not really paying much attention and usually end up having rat stink on my hands.