He has used a similar form of speech before on several occasions when discussing other issues. I actually think it's intentional. There is some pretty good analysis about how Trump very carefully picks his words and structures his speech in such a way as to establish authority while selling listeners on a concept. He always ends each sentence with a "strong" word, repeats it several times, and peppers any broader amount of commentary with several instances of this.
This actually doesn't look odd at all when you consider that. He's actually being clever. He's essentially saying, "she's a racist, and the reason we know she's a racist because I said she was a racist (and since I've established authority with you prior, you will accept my circular logic as fact)". He's just a bit more blatant about it here than he usually is with this stuff. It probably worked with all the people his broader shtick affects regardless. Partisanship is the only thing keeping him from being more effective at what he does.
