Apparently, it is. You continued to live there and did nothing.
Now if I had such a landlord, I would have reported them to the state DOH (or whatever name your state has for such violations). I would not continue to live there month after month and year after year. I would also not bring kittens and puppies by the hoard into such an environment.
Just as you proclaim that the LL consented to the cats by not evicting you sooner, you also consented to the poor conditions by doing nothing.
See how that works?