Nàxiē suǒwèi pínglùnyuán bùguò shì tā de mǎqiánzú.
Those so-called commentators are nothing but his mouthpieces.
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Originally the foot-soldiers who ran shouting before an official's horse to clear the road. Han Yu contrasted their misery with the comfort of ministers in 《符读书城南》: '一为马前卒，鞭背生虫蛆；一为公与相，潭潭府中居.' The figurative 'pawn running errands for a bigger power' is the sense that stuck.
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Mildly pejorative. Often self-deprecating ('我不过是个马前卒') or dismissive of someone else's status.
