"I want a hosted service which is free-libre and free-beer, and don't want the provider to charge or be acquired by a company, and don't want to do anything other than consume their service."
How exactly is that a sustainable model?
As you've mentioned, hosting costs time, which is money. It also costs bandwidth and storage. That gets quite expensive when you're at the scale Gitlab is currently at.
Though I will say that this can be a sneaky business model. Users might not realize some of the features they depend on in the gitlab.com version isn't from the community edition.