It's a manifestation of the entitled cyclist syndrome, and it doesn't do anything to enhance the perception of cyclists amongst the general population. There could be a car park full of £70k Mercs and Range Rovers, whose owners accept that they have to stay outside, but you'll still get the one occasional muppet on an expensive road bike, who doesn't want to carry the weight of a lock with them, and who think they are a special case. Carry a lock, plan your shopping better, or just ride a cheap hack bike to the shops.
Maybe that's because us Englanders didn't vote for Kim Jong Sturgeon to run our government.... We get our booze cheaper than the Scots too, for the same reason.