Because pet enthusiasts are generally highly irrational when it comes to the harm pets can cause? Or more generally, we're acculturated to think of certain thin

Because pet enthusiasts are generally highly irrational when it comes to the harm pets can cause? Or more generally, we're acculturated to think of certain things as normal due to widespread exposure or lack of alternatives. If I punch you in the face, causing you to stay home from work for a few days, but no other lasting damage, I'm a violent criminal. If I go to work while exhibiting flu symptoms because "I just can't afford to stay home", then I'm just a normal human being. If you're raised in a culture where pet ownership is normal, then the unhygienic aspects of pets are just cleanliness-minded-people-freaking-out. If you're raised in a culture where pets are considered "unclean", then you have a different perspective on people's right to inflict their pets on others.