Good noose, bad noose

Noosed black mannequin = hate crime
Noosed white mannequin = hey, it's only a mannequin

It would have been subtler, but much cooler, to have the mannequin wear a red ribbon around its neck. That's what French women did at the Bals des victimes in commemoration of the Reign of Terror's guillotined, mimicking where the blade met the neck.