These types of 'free' sites are over the place.  They are usually based in some sleazy country with lax laws and offer all manner of files stolen from commercial distributors like Turbosquid and Archexteriors/interiors.  I'm not sure what the business model is but this site is clearly offering stolen stuff.   I opened a few files and found many of the internal names to be in an Asian font, a clear indicator that the file had been doctored by a 3d farm in China somewhere.  The only place you'll find free 3D files of this caliber is in the Blender community.