I don't think that was running through the project author's mind as a factor.

It is interesting to just know the reasoning. Nobody is bashing competition. It's just that GitHub has more mindshare and as such, contributors/forks are more likely, and there are more 3rd party integrations.

Again, competition is good for everyone, but let's not bash someone who is just curious why a project author would come to choose GitLab.

It might be that the author likes the fact that GitLab offers free private projects, which might be useful for his other work.

Or likes the interface over GitHub.

Or simply likes going against mainstream.

Full disclosure: I use GitLab since 2015.