I'll tell you no matter what brand of car you have the clear coat will scratch easily and get down to the paint. My guess is that all finishes scratch equally as easy.
You can't see your car at all times so you really can't say what caused these scratches.
Just like when I ask my wife "where did these door dings come from" the response is "never park close to anyone".
Things happen. I used to be very anal about our Honda Pilot getting scratches and dings. After 3 years, I realized there was nothing I can do about it so I quit worrying and getting upset when it happens.