It doesn't bother me that the rodents are gaged in Sims because my Sims take good care of them and they're happy. In real life I could never have pets that are gaged. Same with small aquariums. I can have an aquarium or fish bowl in Sims, but never in real life.
The rodents in Sims 4 also are quite adventurous, every now and then they launch their rocket ships and go to the space. They also have raves and go on all kinds of adventures and send postcards to their household members. One of my rodents apparently wrote a book because he got royalties and another one got in trouble with "Don Landgraab". :D
I can say that Sims 4 rodents are much more free than many of my Sims themselves. The gage is just their home, they're free to go wherever they want.
