I’m glad you mentioned your goals. Without knowing your goals it’s really hard to comment on a question like this. If you were breeding for show then I’d say hatchery stock is a bad idea. Hatcheries are in the market to mass produce chickens at a reasonable price. Each hatchery is a different business with different people selecting which chickens get to breed so there can be differences in the chickens you get from different hatcheries, even the same breeds. It depends a lot on what the selection criteria is from the individual people that select the breeding birds. Some might emphasize one thing, some another. Most use the pen breeding method, they may have 20 roosters in with 200 hens with mating being random. That keeps genetic diversity up but does not lend itself to producing show quality birds. In general hatchery birds often lay pretty well for the breed and generally look like the breed they are supposed to be, but very few of them are close enough to the breed requirements for showbirds to not be disqualified. For your goals hatchery birds should work out pretty well.
Then you have the breeders. These are really varied. Some breed only for what a judge sees at a show. They study the SOP and gain a lot of experience so they can breed grand champion show birds. A lot of these people ignore any traits the judge does not see. These traits could be anything from egg shell color to productivity traits, how well they lay or how well they convert food to weight gain if you are interested in meat birds. A few breeders also breed for the traits, behavioral and productivity, that the breed is supposed to have as well as show traits. There are very few of these. One breeder who bred Rhode Island Reds said there were only three flocks of RIR’s in the US that met this criteria.
You have some breeders that breed less for show but more for productivity, maybe egg laying or maybe meat. A few might breed for longevity of lay. A lot of hatchery birds are bred to lay really well the first two or three years but then the rate of lay can drop significantly. Part of my criteria is to breed for hens that go broody a lot. There are just all kinds of different things you can breed for. But you also have some people that take hatchery chicks and just breed them without having specific goals or any knowledge of how to breed for goals.
If you can find a breeder that knows what they are doing and is breeding for your goals that’s a good way to go. For your goals hatchery birds are probably a really good choice. Another option, especially if you want started pullets, is to contact your neighbors on your state thread and see what they have to offer. I may be confusing you with someone else but I think we’ve discussed started pullets before.
For your basic question, in my opinion most of those negative comments you read are either from people that have specific goals that require birds from breeders that know what they are doing and are breeding for those goals instead of the mass produced chicks you get from a hatchery. Or they are from people that have read those negative comments and repeat them without having the experience themselves. Some have had bad experiences with hatchery birds, but if you hatch 80,000 to 100,000 chicks a week you are going to have occasional shipping problems or problems with individual chicks. I had a less than great experience with chicks from a breeder, I didn’t quite get the exact genetics I expected. When you deal with living animals you occasionally get less than perfect results.