I hope to god this book actually stays canon and isn't immediately overwritten by GW trying to make Tau "actually evil Grimdark".
Tau being the result of just very strong ideological upbringing and conditioning, propaganda and ingrained caste loyalty is so much better than the "uhh Pheromones " bullshit. I like how the Ethereals are presented more like super charismatic celebrities like think how 80s MJ fans feel about Michael Jackson (https://youtu.be/jl-LykdDi7I?si=8wPUuzGclsuWN0fA&t=117) with the charisma of Tom Cruise, George Clooney and Obama rolled into one. It's also interesting how Ethereals are also ""Trapped"" by the caste system. Say you are an Ethereal and you wanted to be a painter? Well go fuck yourself.
Of course GW can't stand actually good, incredibly well thought out lore, so I doubt this book's positions are going to last long.