While I understand the urge to come to this conclusion, it's a simpler hypothesis that they just like the policies these people have pushed for, so much so that they disregard all the negatives that seem to be connected to Republican control (lower life expectancy, ineffective government programs[^1], lower standard of living, etc. You might call it "brainwashing" but that term in this context is too vague; they could claim we are also brainwashed with the same amount of accuracy.
Also, while it isn't your point, this would be a reason they keep getting voted in-- not a reason they run unopposed.
[1] This may be seen as a good thing, for some of them.