One of your links basically asks where it came from, so let me quickly explain, alongside why I'm deadpooling it now:

The obsession with humans evolved from the Sitting Lyra meme. Sitting Lyra is a pretty old photoshop meme, from like the earliest days of the bronies. This human-like sitting is what evolved into Lyra become obsessed with other human features as well, like hands instead of hooves and wearing clothing as the most notable examples.

And that's also why I'm deadpooling it, as our entry on Sitting Lyra already explains that. But yeah, it's agreeable that the entry doesn't really give that away, so perhaps we need to change the title of that one a bit.