We hear and understand your concerns, and we always want to ensure that we’re acting within the spirit with which the community has contributed. Given the varied reactions, as a first step, we’ve decided to remove the pool of Creative Commons-licensed images from Flickr Wall Art, effective immediately. We’ll also be refunding all sales of Creative Commons-licensed images made to date through this service.
Although technically they didn’t break Creative Commons licence, this is just bad ethics. As manager of the community they should at least somehow serve the users, not rip them off.
It is also worth mentioning the last point in their community guidelines:
“Don’t use Flickr for unauthorized commercial activity.
Flickr is a photo community for people to share, explore and discover new works. We also offer tools for the community to license their works to others; if interested, visit our Marketplace.”
What this unauthorised commercial activity means is not explained clearly but quite obviously they are just protecting their own commercial interests.