Ugh, yeah. I'm capable of moving 45 lb plates relatively easily, and I still hate it when people leave the bar loaded because I don't warm up at that weight even on squats, plus I usually need to adjust the rack for my height since I am not as tall as most of the gym dudes. I hate having to unload someone else's plates before I can even start.
Seriously, your workout is not so hard that you can't unload the bar after. I don't know if it's laziness or some kind of passive aggressive territoriality to remind lesser mortals that they don't belong in the squat rack, but it's an assy move either way.