It seems that there is someone out there with an enormous amount of hashing power.

This screencap is taken from Minergate.

His hashrate is equivalent of 1000 Radeon 290.... or 6000 intel haswell cores

Most likely explanation is a botnet.

I read that the devs of BCN use botnet to make fake demand for this coin. Is it true ?

Nope, it's Monero botnet is mining Monero as usual:

That's not the first time Monero developers use botnet and instamine coins

Seriously ?? I haven't heard about it - any links?