To paraphrase Chomsky, the smart way to keep people passive and obedient is to strictly limit the spectrum of acceptable opinion poll questions and allow very lively debate within that spectrum. No doubt Yang is creaming his pants over these polling results.
Whenever I've talked beyond surface level who describes themselves as "moderate", most of the time what they mean is that they're alienated by both the republican and democratic parties. But since their conception is that the entire political spectrum is only the 2 parties, they assume "I must be somewhere in the middle" even if their actual beliefs are much further left than the democrats.