Also at first this objection really resonated with me. I think the meaning of OpenAI has spread pretty well now, and that it's getting to the point where raising this objection is tiresome.
There is an important point to be made about how it got popularized as being open and then they went and closed it while keeping the momentum, but that should be made instead of just saying, "wait, it's called OpenAI but isn't open?!?!"
However, stuff gets started as an open play all the time and gets closed, without open in the brand name, for instance https://ghuntley.com/fracture/ - hence the term https://en.wikipedia.org/wiki/Openwashing