Whoa, there--just because we want to correct rather than vilify people when they make mistakes, it doesn't follow that we want to support either the mistake or the train of thought that led to it (if it was an obvious one).
And Abbott's letter is obviously a mistake. In the space of a couple of sentences, she simultaneously manages to (1) engage in Oppression Olympics, (2) forget the Holocaust, (3) misrepresent the history of discrimination against non-black groups, (4) declare without argument that a word should be used a particular way in a response to an article that in part argued that the word should be used differently, and (5) somehow make light both of anti-Semitism and bullying of gingers (which is a real problem for kids in the U.K., often with sizable life-long psychological consequences on par with the lifelong impacts of racism at least as of ~2010).
That she recognized it was a mistake and apologized without waffling is to her credit.