(metaphor) when someone is undervalued, or losses power or authority, she/he is being bullied by others
Definitions (粵典–words.hk)
語句
某人一旦失勢，其他人就會笑埋佢一份、鬧埋佢一份、奚落埋佢一份、睇低埋佢一份，或者剝削埋佢一份 once someone falls from power, other people are eager to tease, to criticise, to taunt or to exploit them; literally: when someone has fallen, a hundred others will stamp on them