"But now, machines can actually understand meaning."

You're taking this as a given, but nobody's particularly close to showing it's true.

"To verify this, just go to GPT [OpenAI’s GPT-3, a state-of-the-art
natural language processing AI model], talk a bit with it, and you will
be convinced of the fact that the NLP problem is solved."

The fact that OpenGPT will confidently tell you things that are just wildly incorrect is a pretty clear indication that it's not "understanding meaning." Yudkowsky (at least in the essay you've linked to) makes no claims at all about AI's current capabilities. His point is that the inscrutability of a giant array of nodal weights makes it impossible to assess whether an AI is "understanding meaning."

And he's not wrong! But there's a wide gulf between that statement and "machines can understand meaning, and just talk to ChatGPT if you don't believe me."