You're technically right, but you really think people see gitlab.com and gitlab.syncad.com in the same way? I'm just taking about image, and I'm saying this for Hive. If you don't like my suggestion, that's totally fine.
Let me ask this way, is there any other major blockchain whose source code is hosted in your way? Probably not. Again, it's about image. As you wrote in other comment, it's not about my preference. please don't see it like giant company vs small company.
Even though I think Gitlab Inc also wants to sell their gitlab.com in the future as github did, still most people would believe gitlab.com looks much better and more stable than private hosting.
RE: GitHub is now free for teams. Hive project should better be hosted on GitHub