>> 'See this big plant in the middle? That is the one we want! All that little stuff around it is weeds and need to be pulled out of the pot.'
I was totally sharing your amazement at thier stupidity untill I remembered all the times I have asked in a Plant ID forum, or thought about asking, in my own garden, about plants I planted:
"Is this one a weed, or might it be X, Y, or Z?"
(tiptoeing away quietly, hoping that no one in that class heard me thinking what dummies they must be)
I guess it helps if the plants are bigger than the weeds, but in my raised beds, I'm lucky when that happens. I used to go by "the ones that all look the same must be what I planted", but for the last few years, the weeds seem to thrive in regiments of the same thing at the same time. Now it's more likely that a big, vigorous crop of identical seedlings are all the same ... weed!