The problem with the name isn't that they're charging. It's that they're implying that they're something in the ballpark of open source when they're not.
Open AI started with a commitment to being open source (thus the "open"), but then they changed their minds and went closed source. I think in this context, keeping the "Open" in their name is a bit deceptive.
It's not the biggest issue in the world, admittedly, but it does leave a bad taste in the mouth.
What contextual definition of "open" does OpenAI have? A website open to subscribers?
You can scoff at this but Google's models weren't available at any price before today.