I was checking online to verify local stock at Lowes and Home Depot last week. Both websites stated '2' in stock. I had to stop in both stores BC Lowes diddn't have another item I needed, so being curious I checked both stock counts of the item. Both had more than 10, which made me think: if item count >= 2, display 2

Obviously it's not the only explanation, but I assume they use marketing research to help decide what inventory counts to display