I disagree. If one finds a service valuable, it continues to be valuable if you have a new username. I am not excusing Instagram's behaviour. But I am pointing out the fallacy in believing that you own your username.
For the service to be valuable, users are led to believe that when they create a username and a password for themselves, their username will not simply disappear and access revoked at any point in time. That would be quite a useless service wouldn't it?
Indeed, especially for a service like Instagram, your identity is your entire reason for using the service. By taking away the article author's username, they also took the entire account away, including any content he posted. For most users this represents months or years of interactions and activity they can never get back. Depending on how much they use the service, their entire online identity could potentially be lost.
