Where to begin is the question when there is so much absurdity. Although the writer briefly mentions sampling error he really pulls the wool over everyone’s eyes by pretending that is not the major issue in why polling has been off. Polling by taking a sample population that is a fraction of the actual population is in no way the same thing as surveying every member of a small population. Also, even if some SDs decline to answer to a pollster there is a set number that must be reached which is very different than polling to determine the preferred candidates and being wrong later. If the polling reveals enough definitive votes to meet that goal number even with some unknown SD votes there is no sampling error and a margin of error can’t even be calculated. One of the issues why polling has been more inaccurate is the difficulty in polling non English speakers especially Spanish speakers which is not an issue with Super Delegates.
What’s most interesting throughout all this is the Sanders paradox. His supporters and the candidate talk about how polling and surveying is inaccurate if unfavorable to Sanders . But the primary argument as to why he should be the nominee is arguably the most unreliable polling -national surveys for a general months away.