I truly have mixed feelings about this. If the current textbooks are inaccurate or if new information has been discovered, then by all means, the material should be corrected. But to change the information in a text in order to fit a liberal or, in this case, conservative political agenda is, I believe, wrong.
Perhaps in the future, history should only be taught from autobiographies of the people who lived during the time period being studied. Different historical figures will see the current events of their times in different ways. By studying the autobiographies of several people who lived during a certain time period, a variety of ideas and perspectives could be studied, allowing the reader or student to come to his or her own conclusions.