Deleting although sometimes necessary it is a lot easier than, making the effort to ask for a citation and wait a bit, or actively rephrasing or hunting for alternative sources. Despite old information being available from the History, deleting is very severe and out of sight is out of mind, where's content marked with a citation stands at least a small chance of being improved. Some some editors are very good at summarizing verbose articles while retaining important details, turning lists into meaningful prose with an overall flow but I wouldn't consider that deletionism just top quality editing. 
 Haven't asked the Flicker photographer now, will do soon. Will try and bulk up the fair use descriptions.