You don't let your cats out for the same reason zoos don't let their bears out into your fucking neighborhood ya goddamn dingus. They don't belong there and can do serious damage to the local fauna.

also outdoor cats live an average of 3-5 years.

Indoor cats live can for 15-20+.

So sure, if you are pro-premature cat death. Let your pet cat outside.

Because we're more responsible at this one thing apparently. They're invasive. You want to let them outside take them to their native habitat.