"Maybe they are planning for the audience they want rather than the one they have?"

That's definitely a reasonable possibility since it appears to me to be formatted for the Instagram crowd.

"Or maybe they just feel safe since there aren't any alternatives?"

Possible as well but ironic since its creating a space for an alternative.

I like this sites design. Clean, simple, and nothing superfluous. Seems to understand people are here for the user shared content and not the site itself so it stays out of the users way.