I think that’s a lovely page and some excellent sentiments in many areas.
However I feel that it’s important to accept reality and not attempt to redefine words.
A startup is literally defined as to “get something moving”, I would say at this point that gitlab is definitely in the realm of “in motion” and has a significant amount of inertia. It is not in the first stages of becoming a company, it is a relatively well-oiled, thought through and publicly traded company.
Obviously terms can be fuzzy, there may be no single event that defines gitlab as no longer being a startup and no particular point in time being the point of state alteration.
But gitlab as it exists today definitely does not meet my own personal and informal definition of startup, and I suspect that is true for many people.