Cats in europe are far, far less at risk or a risk to the environment then in the US and outdoor cats are not at all a problem.
A cat being run over is rare. Being shot, poisoned or killed by a coyote or other wildlife quite unheard of. And they don’t pose any significant thread to local wildlife.
Americans created that dangerous and deadly invironment for animals themselves. That doesn’t mean that the whole world has to lock up or leash their cats.