I've seen a lot of references to this "Alexander Technique"[1] lately but no indication that it's anything other than the latest trendy pseudoscience that you can conveniently use to explain just about anything. (There seems to be a fair amount of overlap between it and what I can only describe as "rationalists who think they invented meditation".) Does anyone know why it's so popular now or who's behind the push?

[1] https://en.wikipedia.org/wiki/Alexander_technique

The author of the blog produced one of the first online courses in AT and is active on twitter. When that launched, he was the first person I saw talking about it a lot online.

Meditation/mindfulness was growing in popularity in the 2010s and this stuff is just further along the tech tree. It was already well known with actors but the cross-over with meditation-like practices is pretty obvious if you look into both.

The (post) Rationalists you mention are mostly exploring technologies/methods around the connection between mind/body/emotion. There's no single figure pushing it along.