In fact, there is a number of other dero nodes who are reporting the same blockchain as dero.tech, according to logs of my daemon.
I don't know why but they fail to synchronize, some of them get banned.
But how much of the total network hashrate do they command? If they only have a few kH/s out of several MH/s - like dero.tech - then they are wandering in the proverbial woods without a compass... I'm not saying this shouldn't get fixed, just that it's hard to get worked up over.
According to the speed of finding blocks and corresponding difficulty, seems that the remaining part of the network is about one half of the official one (where pool.dero.live is), may be slightly more (400-500k difficulty against 700-800k). I could not find the other pools supporting that side of the network, may be they are private miners or something like that.