Calling it leftover dishwater is the height of ignorance and cultural arrogance.
Hot pot, BY DEFINITION, is about anything goes: it is a communal dish that emerges as a reflection of the tastes of those eating it.
(Except maybe don’t add the veggies too soon, cuz then you get mush.)
Hot pot is not gross dishwater, and screw that random guy for speaking out of ignorance on it.
Telling an entire group that one of their traditional foods is “gross” and “backwards” is using culturally imperialistic logic to invalidate those traditions while labeling those people gross & backwards, too.
Just don’t police my way of using food to work towards a more sustainable future.