You could be right. But it seems to me that part of what drives Ann is the feeling that the Republicans have been very calm about their politics, very factual, and responsible. Republicans want to explain to people what "obstruction of justice" means. Republicans want to discuss the Cosntitution and what is meant by "treason" or "impeachment". Meanwhile, all of that gets lost because James Carville is jumping up and down shouting "SEX! It's all about sex! They is pryin' into our president's sex life!"
The careful approach used by Republicans has frustrated Ann, so she's giving to the Democrats what they usually give to Republicans. This invective-filled approach sticks in the craw of many Republicans (it's just not their style) and it may be that it is counter-productive. But I think it opens the eyes of a lot of people. As you pointed out, Ann includes a lot of truth along with her invective -- that's something the Democrats don't do.
Just as it has been pointed out, Horowitz and others main problem with Ann is that she just isn't polite enough when telling the truth to suit them.
They hint around that her book isn't really that accurate, but then give either incorrect or no examples of error.
The bottom line is that Ann just isn't effete enough to suit them.
To hell with them. They can pontificate their own wisdom until the second coming and no one will notice. Ann, however, relates to people who vote and want the simple story, not meat for coctail party conversation.
Ann is factual, therefore Ann is responsible; if anyone can show me that Ann has not been factual, then I will concede that she has not been "responsible."
As for the point that Republicans have been "very calm" about their politics, I will concede that Republicans have often been very dull and boring in their presentation, which has often made them losers politically, but which has gained them welcome tepid admiration from the people who really count: academics, media people, the New York Times. I take it too many "good Republicans" would rather have Republicans lose nobly than win by making their points in a berserk Coulteresque manner.
For my part, Ann scoring points for conservatism has never lost her any credibility with me, however mad it makes people like Jonah Goldberg, Dave Horowitz, Chris Matthews, Ellis Henican, etc.