Luckily Appsterdam is not limited to Amsterdam. This isn't a pissing match between Dutch cities. It's about international branding. Appschede doesn't sound as good. Most people associate Delft with pottery. Americans have never heard of Utrecht.
As far as most people are concerned, these places are features of Amsterdam. But if you're in the Netherlands, we're a train ride away, and you're always welcome to come up for an event or a meeting.