More than likely the teachers have no idea of the link between this ideology and marxism/socialism. They're going along with the cultural pressure, their jobs are on the line, they don't want to be perceived as contrarian, and buy all the excuses made for why a plain reading of the language isn't actually racist (again, jobs on the line so strongly incentivized to STFU).

Not all teachers go along with it, but like any ideology with the force of population, psychological leverage of guilt, and the threat to destroy careers, most people in any group would comply in a manner that doesn't require deep consideration - in fact, quite the opposite! They need to turn off certain alarms and knowledge to get on the bandwagon.