Your right humans spread them as semi wild pets to protect they food stock from rodents but for Europe that where the romans over 2000 year ago, so i would not say that they are a new emerging existencial thread for the eco system here, if that was the case it would have long colapsed lol.

Not every place in the world is America, there are many places where cats are native, and dont get driven over as much because all is full of cars, i got mine to specifically damage the sorounding mice ecosystem because having the pest control there every six months is expensive.