Instagram's pitch before their users came in-
"Hey we're a free photo enhancing service, come and join us, we don't sell your photos"
Instagram's mindset after they got their users -
"You know what? We need to make some quick cash. We're going to claim all your photos as ours and we are going to give ourselves the right to do whatever the shit we want to do with it, even re-sell it."
If you had intentions to make money, it's perfectly understandable. But who gives you the right to re-sell our content? You never told us that you're a stock photo site when we joined you and you had intentions to re-sell our content, You're luring users to join your service under the guise of 'FREE' while you have malicious intentions inside you.
Now we know what this unethical company is capable of, I am never going to rejoin their service, no matter what their TOS says. Because fuck you, that's why.