Before you start bashing them, I suggest you read the reviews from other customers. Or worse, a member who has done business with them and will defend them & make you look like a fool. So yeah, I will defend Spraygunner as a legitimate site. I’m very familiar with the Spraygunner website - In fact, I’ve bought a hose adapter for one of my airbrushes.
I can’t see what the image is suppose to be you posted is. More than likely you didn’t read the description of said product you received BEFORE you clicked to continue with the transaction. Maybe you purchased something you thought you were suppose to received. Yes, you can buy adapters for airbrush hoses. I own a Paasche single action airbrush that came with the hose. Several years ago, I bought a dual action Iwata NEO at Hobby Lobby. I had to order an adapter (cost less than $10 with S&H).
It’s not uncommon to find a small vinyl hose with a small adapter. Perhaps the airbrush you got is an El Cheapo brand.
So…. I would be imperative what you say in other sites you belong to. Otherwise, somebody will put you in your place hard. I’ve seen it happen. It never ends well for that member in one of my other forum sites I belong to.