I think one thing that struck me from the linked article was the point that the memo wasn't structured to invite discussion. It wasn't "let's have a chat", it was "here's an evidence bomb of how you're all wrong".
I think advancing points is fine, but if you're after productive discussion rather than an adversarial debate, you need to proactively invite discussion. And if an adversarial debate was what he was after, that does strike me as inappropriate work communication.
It was a politically charged topic, he would have been crucified either way.
But by phrasing the memo the way he did, he covered himself legally.
I wouldn't be surprised to hear everything was run by a lawyer first.
Others disagreed.
Even slatestarcodex argued a little for both sides.
Its clear scientific consensus has not been reached, and people need to discuss this openly with out censors.