Why? There is enough space on the parking lot

A distraction for sure, doesn't excuse for the inconvenience of course, but if you ask why is then is because:

1. People are buying increasingly stupid ass huge cars
2. The ability of the average driver to actually drive well is decreasing as much more automation/aiding systems are injected into the driving experience
3. It follows that then people will often graze the cars parked just aside theirs, when manoeuvring into or out from a parking slot, especially on the corners of the bumpers
4. Any owner will then try to avoid this by moving his car outside of the possible trajectory of the driver who parked/will park the car just aside theirs and who most likely can't park a car, while yet choosing to buy a stupid huge ass car, and they do this by moving the farthest away from the rear parking line.

Of course they could have bought a small car instead and avoid invading the walkway, a small car surely also would have paired well with the smallness of their brains and/or appendages, but the lack of taste is since long time well past endemicity levels.