Well they basically cancel each other out making the rescuing pointless. Every animal that is bred takes away a home for an animal that is in a rescue. You can't say that you are saving the animals if you are condeming others. You might be removing them from a bad situation, but not rescuing. Let's say rescue 3
cavies and are fostering them but then breed a
cavy and have 3 babies. Those three babies are adopted out (actually I guess a better word would be sold since they were never homeless) but the three you are fostering are not. Well now those three
cavies are still homeless and could have been adopted out in place of the three babies. They just can't go hand in hand, the principles of both are on such opposite ends of the spectrum.