Why was the post World War I period such a hotbed of race riots, with white and "near white" groups primarily being the one's rioting? What *white* anxieties were causing them?

Though world war 1 and world war 2 have very different conflicts, and circumstances, they also had many simularities. they each fought issues so urgent that every country, felt the need to fight for the side that they had though was right. each country involved had suffered from losses incredibly severe; only in an effort to win.