When you do this, it's at the expense of other people. The people in those stores haven't consented to being a part of the uncomfortable situation you've put them in, and they're probably creeped out by your presence. You're also harming the reputation of other AB/DL people (and, to some degree, kinky people more widely) by representing them this way.
It's incredibly inconsiderate, selfish, and gross. Especially since children could have seen you in those locations. I'd also question the motivation.
It's one thing to be fully clothed with a bulky diaper underneath that other people might notice. It's another thing entirely to be almost naked from the waist down while only wearing absorbent underwear which (as far as others might know) could be holding your urine and faeces.