How do you guys feel about indoor only cats?

I'm genuinely intrigued to see people's POV on this as I had a argument with someone who thinks it's unethical to let a cat run free outside, I need y'alls advice (probably going to post this to r/cats aswell). I'm young and I want to understand both sides. I'm very happy with my cat being an outdoor cat who comes inside to nap and relax

Quick edit: I do also believe it depends on where you live, how you live and the situation, among other things.