I think it's a bit insulting to say that black voters have been duped by Democrats into voting for them, and that they don't know what's good for them. Democrats have been winning the votes of African-Americans since 1936, and the vast majority since 1964. That ain't because black voters are confused or tricked; they vote according to what appeals to them most, just like white and other voters. Republicans shouldn't ask for the black vote by claiming that they've been voting wrong this whole time because they're blind or stupid. A Democrat wouldn't ask for the votes of white evangelicals by telling them "you're been voting the wrong way, you've been duped." They would offer an alternative that is honest and tries to understand their community's concerns. Trump's outreach is based on stereotypes about African American communities that aren't true; he isn't in 4th place among black voters for no reason. He has earned his position in 4th, just like she has earned her 80-90% among them.
I agree with you that saying black voters are being duped into voting for democrats is rediculous, but at the same time with regards to evangelical white people that is exactly what the democrats do. The premise of the book "What's the matter with Kansas", which basically states that middle class whites are being duped into voting GOP by race and social issues, is an article of faith among most dems. Heck, there are a large number of posters here who believe that anyone who isn't a democrat is straight up evil or stupid.
