IG can request providing an ID before validating your account (I believe Facebook has this protocol in place already), but as far as "joining the Internet" goes, it's almost impossible to regulate with the existence of public Wifi, VPNs and other various technicalities. Your broadband provider sure requests your ID when setting up your contract.
No one on this thread (or on Niomi's IG) supports bullying. As far as I can see, the comments left on her IG are not vile comments meant to shame her (as compared to the usual "you're ugly", "you're fat" etc that you can see all over IG / Twitter). The criticism I saw on her IG was quite polite and simply illustrated opinions in a civilized manner. No one called her names or insulted her. She is acting as though people are bullying her mercilessly, but it is simply not the case. When you release a song, a movie, a book, a product, you receive good and bad reviews publicly. It's part of working in a client facing business (because yes, she works in a client facing business given she has a sales / promotion function on behalf of all the brands she represents). She simply has unrealistic expectations.