I think graduate students are aspiring members of the petit bourgeoise, and typically are going to come from such families anyway, and shouldn’t dilute real workers’ movements with their quite distinct interests.
So, workers' movements don't benefit from their members going to graduate school?
Perhaps you have identified graduate school students as aspiring members of the petit bourgeoise because only individuals with such aspirations would rationally pay for graduate school in today's system.
I don't think anyone is discounting the problem -- but they are reacting to the scale. Its like you jumped onto a story about a child stepping on a landmine to complain about your paper cut.