I don’t understand the logic of the “shy Trump voter” theory at the individual level.
Why do these voters believe they need to hide their support of Trump? Most Trump voters live in areas where the overwhelming majority of people also support Trump. And most Trumop voters believe that the majority of Americans support Trump, and they receive a media diet the reinforces that belief.
So who exactly do they think they need to hide from?
Moreover, if they social desireability theory were true to generalizable extent, we should expect polls to underestimate Republican support in Democratic areas and underestimate Democratic support in Republican areas. And yet we routinely see the exact opposite. Especially in 2016, polls underestimated Trump most in deep red states. Why would Trump voters in Oklahoma be more shy than Trump voters in California?
Subconsciously they still know they're a minority, at least the smarter ones.
Not just that. On some level, they know that supporting Trump is
wrong, un-American, evil. On some level, they're embarrassed and ashamed. Maybe not of being Republican, or conservative, or of their beliefs, but of supporting a deranged and abusive jackwagon as their leader.