I think it all depends on how you use them.

I think if you have wall to wall rats in them yes I think it is inhuman.

But if you just keep 2 to 3 in them I don't think they are.

I have a rack that hubby built from patterns I found on this group.

I keep 2 rats per tub.
Except for right now I have babies so the moms that have babies are in a tub with babies since they are growing fast I took the females that didn't have babies out and put all 3 in a tub for temp purpose til hubby can build me another rack.

I think the tub/rack system is very practical. Esp when your talking space and a number of rats.

The racks don't take up to much space , they are easy to clean out, it is easy to see in so you can keep checks on your little critters and all my guys seem just as happy in the rack as they did in a large cage I rotated them into for a while.

The large wire cage was and is a pain to clean out.

I think it all has to do with the number of rats you put per tub and the way they are treated as far as food, attention and the cleaniliness of their tub.

I think the rack and tub systems AWESOME! I'd never have a bunch of large containers or cages sitting around the house full of rats.
Not for breeding purposes anyway.

Maybe for a pet rat or two I might have a cage but not for the number of breeders we have .

One other good thing about the rack system is they can't or aren't very likely to chew out . With the containers you mention I have read lots of problems with chew outs.

I have 6 cats . My rats can't afford to chew out!

Hubby and I were both a little concerned about the space when I first got my rats. But they seem totally and completely happy in the tubs and even jump to go back in when taken out for to long .

We even built a play pen for them to run around in as we felt they might need and enjoy some excercise but that didn't last to long as all they did when we let them out was huddle in the corners together. They didn't run around or play like we thought they might.
We were trying to make up for the lack of room in the tubs but evidently it wasn't necessary.

Like I said even though they are basically food they still deserve the respect and care of any other animal you have in your house and I think thats what makes the most difference for quality of life.

We also feel very stongly about human deaths.
After all they are living breathing little beings.

We maybe different than most breeder here but it works for us and them.

Just my two cents from our experience.
rhsm