Oh, the righteous outrage!
Look, you’re not paying anything for this service. Neither do you pay to use Facebook or Twitter. So, you’re not a customer. So, essentially, they can do whatever the fuck they want. This is not hard to understand.
I have had a pro account on flickr exactly for that reason. And with their new app, which, frankly, is pretty spectacular, I might use it more than I did in the last year or so.
I don’t have a problem with paying for a service. If every Facebook user would pay $1 a month, they would make a shitload of money. And I would pay a buck or more to use a service I like.