Yes, but in so far as I can see, the incidences you quote are of teachers geing asked to teach children to think critcally about US history, to acknowledge the parts racism, sexims ans homophobia have played in the formation of American society and to challenge the ongoing pernicious influence of these things. That's not Marxism, just common decency.

Donlt fret about Marxism in America, Even the most left-leaning American writers on Medium are - from my English standpoint -slightly to the right of Attila the Hun!