Assuredly so long as humans write history books there will be a subjective element. Historians can judge the quality of works, so writers of history should strive to be as accurate as possible as well as fair and balanced lest history cast their works aside as biased, inaccurate and/or false. Such discarded works may have value for readers of historical fiction.
Did you ever read the formerly classified air force history of giant alien crabs attacking Los Angeles and moving with stealth shrouds under cover of darkness to scuttle inland to conquer Area 51, and was the treatment fair and balanced in the treatment of what the crabs called the partisan resistance, deplorables?
Garrison Gibson: books and blog 