Luc, I think because you've decided that if someone uploads a photo that is "clearly" (from your point of view) off topic, then they have a sinister motivation (manipulating the point/vote system). That lends righteousness to your argument but is nonetheless a mistake to make this assumption.
SP is not "swamped" by anything. Look at the routes and mountains and TRs that interest you. Watching the live feed of incoming images is just a receipe to make you angry because they support many diverse topics that will never interest you...such as high points of very low and flat countries.