Rubber hose animation
en.wikipedia.org
en.wikipedia.org
Traditional hand-drawn animation is also a very time consuming process. If your animated characters have more structure to their anatomy, you have more things to have to worry about when it comes to maintaining consistency of proportions and the "physics" of what your characters can/can't do. A rubber hose doesn't have a joint that can only bend in one direction, for example. When time is of the essence, and in an era where animation studies were small struggling companies trying to sell their shorts, you need to find ways to reduce the amount of work.
https://en.m.wikipedia.org/wiki/Disney_Animation:_The_Illusi...
If you check out YouTube you'll find a lot of examples.
There's even a few rubberhose plugins for after effects if you want to get that effect.
https://www.adobe.com/uk/creativecloud/animation/discover/ru...
It's hard to imagine something like The Fox Chase[1] in a different style; the lack of distinct joints and extreme flexibility make for things that wouldn't be believable in a more realistic style.
So, a little of both.
Your answer is largely correct, rubber hose refers to the limbs which are thick black lines that lack obvious joints, instead they have the rubbery(bouncy) movement you've described.
(1) https://www.adobe.com/uk/creativecloud/animation/discover/ru...