@georgia I haven't read the whole text, but for what I read on the pic you posted he's totally right. I don't think he's talking about yoga as an impossibility, just about the futility of words, even sacred words, to do that union. If it's as I think I can only agree with him when he call it a foolish talk. It's also stated on the tao te ching:

Too many words hasten failure
Cannot compare to keeping to the void