Some sites want us to think it's in stock in hopes you'll order something else as well. And, since you have an account set up, you will use them in the future. It's a BS move to NOT state explicitly right up front they are NOT in stock. A site that does that gets ZERO business from me.
I bought two 17 round mags from Tactical Advantage and only after I ordered did I realize they were not S&W factory mags. They display the manufacturer they are FOR prominently but made no mention they were Pro Mag. When I realized it I wrote to them asking to cancel my order as it wasn't shipped yet and they said they would charge me a re-stocking fee of 20%. So I accepted the order and will resell them only in my ad I will be upfront about who manufactures them.
I have NEVER heard of a restocking fee for a product that wasn't even shipped yet. It's probably against the law.
During this demand crunch we learn who takes advantage of us and who doesn't. We should reward and punish accordingly when the demand eases and they come begging for our business.