The takeaway from the article is not that people lie, but just that people who are more trusting (according to the GSS survey) are more likely to take surveys and are also more likely to vote Democratic.
I think this is built into the fabric of political views. If you're cautious about other people's motives, you'll want smaller government (less authority over you). The more you think folks are generally trustworthy, the less you'll fear having a larger government.
I wonder how many in any set think similarly about these surveys. I assume distrust is the most logical base state, hate unknown callers / blind interactions as sources of fraud, misinformation, and marketing (which I view as often leaning against the borderline of the former).
I would also hope and assume, given the religious bias correlated with Republicans in the US, that many of them are more trusting of others.
If people in Congress or the President wanted to, they could absolutely find out who answered in polls that they'd vote for a candidate.
That might have been true in the past.
From 2016-2020, Trump supporters have been loudly and repeatedly called racistNaziMisogynistHomophobe, or the polite version, "deplorable". That is not an environment that encourages honesty.
What policies did Trump enact which you think animated the support that Trump received?
Answering your question: I didn't have any theory relating Trump's actual policy implementation accomplishments to support. Rather _my opinion_ is still a _belief_ that most who support the 45th president as a candidate do so based on blind charisma and an extra sweet helping of wishful thinking.