Because if you don't pay you are excluded, while projects that do not even make sense to exist and do not even start if they pay are considered real OS. The worst thing is that even Wikipedia does not consider them if they are not reviewed by Distrowatch. What common interests have they seen that Distrowatch is not an official body and Wikipedia claims to be free information?
Corruption is everywhere, like the stupidity of those who, without even asking, raise some private sites as open source gurus. We also consider the fact that the judge, the jury and the executioner is a physiotherapist who has a passion for tractors, not a degree in computer science.