Are you saying that as soon as I signed up to IG with an email address and started posting pictures, IG then knew who I was to the extent that they can prevent

Are you saying that as soon as I signed up to IG with an email address and started posting pictures, IG then knew who I was to the extent that they can prevent impersonation after I delete my account? I'm skeptical. They do not need to keep a record that I previously existed in their system. There is literally nothing other than marketing/bizdev that derives value from this.