From that picture, it kind of looks like that'd be a BETTER lot than many I've been in to do what that guy did. There is a nice long lane behind him where people can "pile up" without blocking an exit or anything. Though he is a bit close. I don't think it's an especially big deal but I can see how it would be irritating. More so in other parts of the lot, though, or in other lots where things would be more cramped.
A few points in opposition. 1) Since the holidays DO cause stores and lots to become more crowded, however, I'd think that doing your best to be speedy when putting your packages away and getting ready to vacate a space would be just as much a courteous, expected thing to do as not blocking the lanes while looking for a space. After all, you've done what it is that prompted you to need a parking space; now clear out so others can get on with their day. Their time is just as valuable as the time of the person getting ready to leave, and
no one likes circling a lot over and over and over and over... There are more or less rude ways to wait for a specific space to clear while someone gets ready to leave, but in and of itself, that's not necessarily a rude thing to do. 2) The act of asking "coming or going", by itself, is not rude either, and I'm surprised you'd find it so. If the lot is jammed and there are more people than spaces, asking people who look like they're getting ready to go if they are indeed nearing being ready to go is... well, what else WOULD you do? Especially since if you DON'T ask, and instead just start waiting, there are some people who will put all their stuff in their car, check a few things, get something else
out of the car, then lock it up and walk away - they actually had more errands to run and had no intention of clearing the space yet. All the while, there was a person waiting, and the person already in the space studiously avoids eye contact so as to not inform the waiter that they're not, in fact, leaving. This to me is far more rude.
All of that said: I am car-free and perfectly happy to be so (the only time I get a huge load of groceries is if I have a ride). This is just another reason why.

I live in the core of the SF Bay Area, which is...
decent, for public transit. It's not great, but usually serviceable, with
occasional flashes of "actually really good."
This puts it near the top of all areas in the US for transit, sadly.