I don't know much about the US, but here in Italy, until one or two decades ago, some people say history textbooks tended to have a left-wing bias whereby communists in the 20th century (esp. WWII) were depicted in a more favourable light; and then they were called out for this and they've probably overcompensated for that. (I don't know much about 20th-century history from anywhere else, so I won't judge myself.)