I tend to try to not get in battles with people over that type of thing. Several years back I would lecture people on proper bra fitting: how all the sizes technically work, how you shouldn't commit to "sister sizing" because it's just encouraging the bigbox bra manufacturers to continue making the same limited size runs that they want to make (34-44A-D/DD, essentially) to raise their bottom line, instead of actually creating all the sizes women need and
are, etc... but overall it didn't seem like information anyone wanted to hear. Apparently most women would rather wear incorrectly fitting bras that they only have to spend $10 on.
So at some point I decided that that's their choice and to mind my own business.
Speaking of which, in the Seattle area there are Nordstrom Rack stores (basically the clearance/overstock stores of all the surrounding Nordstrom stores), and I've actually been able to walk into a store and buy a bra that fits me off the rack and it's so surreal compared to my normal shopping-online-routine.