I think there's more stomach for it than you do, but do agree some large subset of the population thinks that e.g. they ought to oppose the so-called "death tax" because it'll apply to them or anyone they know (it won't).

There's also the issue of a large proportion of the population not even understanding how progressive income tax rates work.

Well to be fair, the Democrat's contortions on the SALT deductions certainly didn't help them (but if the only people you talk to are affluent coastal liberals then I could see why you'd support such a regressive policy).