Russia’s threats were widely publicized at the time, so the threat of nuclear war was not at all classified information.
Now, let’s look again at the direct quote from the NYT.
So I’m not really sure what you think Biden did wrong here. Especially when citing an article that specifically says that Biden didn’t say what you say he said.
You do realize that the journalist had other sources in the administration and is not just reporting straight from Biden’s mouth, right?