Here is a perspective from someone who has owned an inside/outside cat for the last 12 years. My cat is independent and resourceful and yes, contributes to ecodestruction by killing birds and mice occasionally. To me this is negligible compared to the ecodestruction of simply existing in a city. If I lived in nature I would not have a cat. I don't think you can conflate my cat killing a pigeon twice a year in an urban environment with destroying the ecosystem.
It's also disengenuous to ignore the quality of life improvements of having a cat who is free to explore vs. one locked in an apartment all day. I recently moved and am now experiencing this and it sucks. I feel terrible for restricting her freedom and she is visibly less happy. If you think animals are sentient and have emotions, and you care about the environment, then none of what we are currently doing makes any sense.
Yup, and I'm the only one with agency in the whole world. It's all about me.