Re: Ofcourse they went public...
"Maybe I'm too cynical here, I cannot rule this out, but in my opinion Gitlab didn't have a choice but to go public. For the simple reason of damage control."
Yes, they did the right thing whether it was intentional or unintentional. Covering up stuff ups never works and always makes the company look even worse (here's looking at you TalkTalk).
That said, this time GitLab really got lucky and they must significantly improve, and test, their back up capabilities.