Wait, what? Backing a truck in makes it a lot easier and safer to leave (better visibility of traffic and pedestrians). It has little to no effect on anybody else other than maybe having to wait for them to back in.
When I drove a company van for work, they forced me to park like that. Their reasoning was it's too hard to see to back out and could lead to accidents. Which never made sense, because backing into a space has the same issue if the space is flanked by two parked cars and I can't see well enough behind me to line it up.
You can see both sides on the mirrors so it's almost impossible to hit the cars next to you and it's very unlikely there's someone standing behind you on the parking space.
Fender benders on a grocery store parking lot when backing out is probably the most common type of road accident.