Posting to Instagram really isn't the same as posting a photo to the internet in general though. That for-profit business is running the software, hosting the s

Posting to Instagram really isn't the same as posting a photo to the internet in general though. That for-profit business is running the software, hosting the servers, and writing their own terms of service, they can block what they want at that point. The real fundamental change after the dot om bubble was that the open web effectively died and was replaced with a handful of walled gardens. If you have your own site and post pictures to it there are very few that can stop you, posting to Instagram and you're effectively politely requesting a company to take rights to your photo and host or online if they would be so kind.