I highly dislike centralisation, especially if it is centralisation on proprietary services. The more the merrier, people should feel comfortable using different sites and not chastise the underdogs.
But in the reality of things, having a central repository with a voting system that is significant and trustable enough is very important - for example, when you need to choose between apparently similar libraries. And a star on Github - rather, a good number of stars - does count much more than any number of stars on any other service in the programming community.
I say this not because I have a particular love for Github - I also use Gitlab for some projects, and it's very good - but just because it's the way it is.
Yes, they may count more on the most popular site but it doesn't have to matter. When enough people see it on Hacker news or Reddit it will be known anyway and it might get start on the site it is on. You can just judge it from a different scale.
And if the most popular should always win there would be no Linux, Windows is still much more popular.
I highly dislike centralisation, especially if it is centralisation on proprietary services. The more the merrier, people should feel comfortable using different sites and not chastise the underdogs.