I disagree. The connection between lynching and the way black people were treated is not obscure. It wouldn’t have been nearly as much fun to tweet something like “@LorrettaLynch: why not let a grand jury decide?” With the “lynch” tweet he can have his snicker and “we want our country back” moment and pretend that he wasn’t using the dog whistle.
The fact that Trump’s son-in-law and daughter are Jewish has been known for a long time. The fact that he wasn’t sensitive to the symbol is even more damning if he not only “loves Jewish people” but actually has people he loves who are Jewish.
In every Digital Literacy lesson that students (of all ages) are required to take, a major concept is that you can’t take back things that get posted on the internet. As a public figure, regardless of whether you are a politician, a professional such as a lawyer, a physician, or a teacher, or, really, as a human being who is concerned with what other people think of you, you are careful what you tweet or retweet. As a public figure (especially one who believes that he is qualified to govern a state and who is currently a surrogate for a presidential candidate) he should know to read his postings for potential problems.
We would not accept this sloppiness from any other public figure. We should not accept it from these public figures.
Having said that, you may have a point that the charge of racism may lose its impact, but I can’t help but think that we still need to point it out. Perhaps the response should be on the incompetence of a campaign and candidate that doesn’t focus on management. That might hurt him worse than the charge of racism. But racism is still racism, and being insensitive to the symbols of past abuses is incompetent–for those who use them and for the audience who receives it.