With a project like this, it doesn't matter if it's technically open source if they don't make it practical to self host intentionally. There are so many components and nuances in such a complicated system that figuring it out or documenting it yourself through reading source is again, free engineering work for them.

Not supporting self-hosting is a cost-based decision, saying "well I'll figure it out and do it anyway" is just encouraging companies with open source offerings to act like this. Open source is only have the equation to make something self-hostable in any practical sense, the other half being accessibility.