Just like someone said before, if you don't care to learn how to properly care for an animal you voluntarily keep, then you should re-think your choice of pet.
Not everybody who owns a cat or dog can't afford to give it the best medical care, but does that mean they're neglecting the animal if they can't take it to the vet for regular checkups? I think if you are loving and caring to the best of your abilities, then that is usually good enough. Even better if you educate yourself to continue providing better care if at all possible. I'm the kind of person that instead of getting angry about "mistreatment" I try to educate the person as to what they're doing wrong and hopefully they are receptive about my attempts to educate. And I try to educate myself as much as I can which is a big reason why I'm around here so much. Education.
A couple examples. My daughter wanted a turtle for Christmas. I looked around and found one on craigslist. Once I found the one I was going to get, I took it upon myself to learn about the animal and how to best care for it. When I got the turtle, it was obvious it was neglected, even though I had never owned a turtle myself. Now, it has a very good home, diet and is healthy (confirmed by a vet) and by all appearances is happy.
When I was new to fish keeping, I bought a variety of fish that due to a newbie mistake, weren't compatible with eachother. Even though I really wanted to keep them all together, I realized that it wouldn't work and returned the offending fish back to the LFS.
Not trying to sound arrogant or self righteous, rather just giving examples that I understand the topic at hand and fully agree with the OP. I hope this discussion continues to be productive and not turn into a flame war that gets locked.