We need a word that we can tag onto our posts that basically means “yes outdoor cats harm the environment and is bad for the cat, yes you should spay and neuter, yes I will register the stray with the county, check for a chip, and monitor lost posters to make sure the cat is not pre-owned before I adopt it, yes a cat is for life and I made this decision with sound mind, yes I know X food is not good for the cat, yes I know to get vaccines and regular cat care, etc etc etc”. Or, perhaps people can just assume good will from other humans and not throw unsolicited advice their way every time they post a simple photo of a cat.
I think (without any research, just from vague memory) the ear clipping isn’t actually all that painful to the cat, and the benefits of an immediate visual identifier outweigh it. I wouldn’t even know where to look for a cat tat.