That's more of an indication of how our modern sensibilities have changed.
When I was a kid I was taken to the local zoo, where lions were displayed in small, bare concrete cages. I felt sorry for them, and did not enjoy the trip. But that doesn't mean the zookeepers were bad people, people just thought differently about animals in those days.
You're right, it really is too difficult to live and let live. It's really too difficult to think, is everyone benefitting all that much from the pain I'm inflecting on whatever I'm hurting. Please, these are adults that knew what they were doing and that the pain they were causing didn't satisfy some need, but some want. If you don't want to go down in history as an asshole, don't be a dick when you or your tribe are only benefitting beyond basic needs and necessities.
A lot of people are okay with testing things like drugs on animals. You can at least imagine a scenario where Edison was driven by concern for public welfare, thinking the higher voltage used by Tesla was going to cause disasters and trying to make people aware of the danger.
When I was a kid I was taken to the local zoo, where lions were displayed in small, bare concrete cages. I felt sorry for them, and did not enjoy the trip. But that doesn't mean the zookeepers were bad people, people just thought differently about animals in those days.