Except this is exactly what the author of the original article is attempting to do, and that is what I’m responding to. She is positing that Sanders and his supporters are a malign influence on the Democratic Party and lead to the downfall of Clinton in 2016 due to vote switching. Therefore, the comparison to Clinton supporters’ own vote switching is necessary and relevant.
If Sanders supporters vote switch at lower rates (using Clinton’s own voters as a baseline), then Sanders actually had a net POSITIVE influence on Clinton’s electoral outcome. This refutes the author’s implicit argument against Sanders. The fact that if no Sanders supporters had vote switched Clinton would have won is pedestrian and not relevant to whether Sanders is a malign influence. Sanders should be compared RELATIVE to Clinton. Comparing his influence relative to absolute perfection and then claiming he falls short and therefore Clinton’s loss is his fault is totally absurd.