Well sure - they put one sticker on and it solved everything. Are you suggesting they should have put a sticker to adjust the price of a single item and then also put another sticker on to hide the 3x item? That’s not only a waste of stickers and time, it also really doesn’t add or remove anything from the situation.
I’d argue you are the mildly infuriating part of this scenario at this point.
It “solved” the singular and bulk pricing. If they chose a lesser value for the single item, then the more you bought, it’d get more expensive.
They gave you the cheapest price for quantity. That’s both a scenario and reality.