I think the author's chosen name for the phenomenon "Nicespeak" creates a cognitive distortion that muddies what I think her point is. She is not talking about being nice rather than being rude. Rather she is talking about being authentic and human rather than becoming an automaton channeling the will of the powers that are compelling your speech.
Her example of the fast food worker is they're channeling the brand of the franchise "whether or not they made sense in a given context". "The idea was to subordinate the personality of the individual speaker to a centrally designed corporate voice."
Her example of the workers in the public-private partnership of academia describes having to conform to the rules of the corporate information-hiding language game in order to compete with others for funding. "If they do not claim to be 'excellent', they will inevitably come out losers."
In these cases the casualties are authenticity, connection, a frank assessment of and confrontation with reality, and humanity. In lieu of them, we've created a network of symbols and signs overtop of existence that pretends to be true reality, but really distorts it to the benefit of the holders of power. This network of symbols comprises brands, mission statements, corporate personalities, metrics that yield to Goodhart's law, empty buzzwords and hype, etc, etc, etc.
I think that's what she's criticizing.