This post at Socialist Unity (“China issues report on human rights in the USA“) recalls the 1930s and 1940s, when Soviet propagandists responded to American accusations of engineered famines, murderous purges and slave labor camps by saying (in one variation or another) “And you are lynching Negroes.”
And yes, to the lasting shame of the United States, some African-Americans were being lynched. But that didn’t make the original accusations any less true, or the USSR’s horrific abuses any less worthy of attention.
Update: See also Howie’s post.