Yes they are that incredibly stupid. And yes they vote.

You know who else are incredibly stupid? Anyone who doesn't vote, therefore empowering them, anyone who says that Democrats are the same as this orange parasite and the cancerous political party that props him up.

bOtH pArTiEs ArE tHe SaMe LoL aMiRiTe is just another way of saying "I'm too lazy to do any homework, I'll make an opinion based on what some Twitter posts tell me".
Those Twitter posts are targeted at these idiots, they are designed to "divide and conquer". And of course, they are too mindlessly lazy to figure this out, in fact they will forcefully reject this, as they give themselves permission to remain lazy. "I give myself a helluva lot of leeway, but this other thing I declare to be black & white with no shades in between. mUh PuRiTeH!"