The message asks users to explicitly deny permission to Instagram to use and share the content posted on their profiles and also asks users to mention in the post that "the content of this profile is private and confidential."
A part of the message says that "NOTE: Instagram is now a public entity" to mislead users.
Here is the message:
The message is now being shared by hundreds of people through Instagram stories and posts.
The news is fake, similar messages had hit Facebook as well in the past and even this message seems doctored where the word "Facebook" is been whited out from screenshot of an earlier message and "Instagram" have been added (see "Instagram" in the first line). The message says the deadline is today but doesn't mention a date and the message is being circulated from over 2 days now, so you are most probably already late.