Take all this with a grain of salt, as I'm about to get vague and handwave-y. According to some article I read [citation needed], the fact that their interface

Take all this with a grain of salt, as I'm about to get vague and handwave-y. According to some article I read [citation needed], the fact that their interface is crap actually drives more pageviews. E.g., that profile pictures are distorted is searches actually encourages people to click through to profiles to see better-looking photos. So poor usability actually is a feature. Which comes back to the old argument about advertising-driven revenue models resulting in poor user experiences, since the "user" from a revenue model is the advertiser and YOU'RE the product.