"COPYING" is abused. RIAA and other organizations have really tried to grossly expand the definition and that has tainted the discussion. For the next paragraph, "COPYING" means literally using the same assets (or a digital replication).
The line is drawn at "literally copying assets". Putting up your own assets that are inspired by another site isn't copying. Putting up another company's assets (or downloading and self-hosting other company assets) crosses the line.