First, would anyone sign a credit card agreement that said "we can change the terms at any time without telling you"? No. In fact, a material change to a contra

First, would anyone sign a credit card agreement that said "we can change the terms at any time without telling you"? No. In fact, a material change to a contract means that either party can back out of the original contract. This is how people get out of cell phone contracts when rates are changed without having to pay the ETF. Second, yes, the new terms are exactly why people are pissed. They don't like the new terms and they are upset that Instagram would form something so distasteful on them (or try to do so). Just because Instagram is legally protected doesn't mean everyone should be happy about their decision and keep using the service. That's how a market economy works. Just because something is legal doesn't mean it will be popular in the market.