I can't say rhat I am a fan of the way any delivery drivers park/idle, but they have a job to do. They are literally breaking their bodies to do it and the city is generally too crowded to find convenient parking close to their drop offs.

The real solution would be to convince the companies they deliver for to lower the volume of deliveries a driver is expected to do in a given amount of time, but there is no way in hell that is going to happen.