This concept was introduced after fans complained that the initial T'au codex described the T'au in too much of a positive light, and that they were too "good" for the grim, dark Warhammer 40,000 universe. This also led to the introduction of the Vespid Communion Helms, which have a much clearer Orwellian feel that the Vespid are being directly manipulated by the T'au thanks to the helmets that are supposedly for "communication purposes."

Very cool of you james workshop

I originally thought the caste system was "problematic" enough to leave the Tau as visibly "Better" but still with hangups but they had to go and do it to 'em anyway.