Right, but game theory tells us that for every single position, perfect play either leads to a win for one player or a draw, and for every position, there is a best reply.

To the extent that an AI approaches perfect play more closely than a novice or masters from the 19th century, shouldn't we go learn from the AI?

One interpretation of Stockfish here is 'I don't think this is a very strong opening'. To the extent that it's correct, stronger players will not play that opening very much, so spending time to learn it seems potentially wasteful.

Chess engines (I suppose that could be called AI) as well as databases of games have developed opening chess theory very significantly because of these reasons.

For perspective, Bobby Fischer created a version of chess which randomized the game because even in his day, he was annoyed that some players that he felt were far inferior at playing chess, could actually better memorize opening lines and enter the mid game with an advantage.

So the answer is that players very well have been learning from AI.

>To the extent that an AI approaches perfect play more closely than a novice or masters from the 19th century

AI has become better than even the top chess players of today.