Honestly the first thing that came to my mind was that they wanted to park between the two posts because they were going to bring something out heavy and they needed to load it into the back of the car.
One of the poles would still have been in the way, especially if it's something large like a TV or lumber being loaded into the vehicle (have to account for the cart that the thing to be loaded is being carried on as well).
Just looked at the picture again. The back-end of the car is centered between the two poles, giving the maximum amount of space on each side of the vehicle for the poles.
Parking in the left spot with the vehicle 3/4 in the no parking area would allow full access to the back for any item. The right spot would be completely open and driving nose in would allow the person to get in and out in the other no parking area on the opposite side.
There was no reason but sheer laziness for parking like this or mental incompetence.
I'm not saying they can't park like an ass, I'm saying if they could backup properly they could still easily park in one spot but over the line in the spot and still have complete access from all angles.
Your whole argument is based on the assumption they've been there for just a few minutes to load their trunk. This is just plain speculation, you don't know that. If you need to load, just park the way you're supposed to. I think (European) Humanity will understand you're an asshole if you park like that.
This is somewhere in Europe, most likely Germany (or reasonably close regarding driving license requirements). Most people park forwards, it's not unsafe. People (generally speaking) know how to park without endangering others.