The University of California considers statements such as “America is the land of opportunity” and “everyone can succeed in this society, if they work hard enough” to be microaggressions  that faculty should avoid.
Source: Bloomberg/Koch opinion piece on free speech on college campuses. WSJ 5-13-16
I’m betting you and I can find many members of every group in America for which the above statements are true, including a few hundred million “marginalized” immigrants in the 18th, 19th and 20th centuries (like my ancestors).
 Microaggressions are the everyday verbal, nonverbal, and environmental slights, snubs, or insults, whether intentional or unintentional, which communicate hostile, derogatory, or negative messages to target persons based solely upon their marginalized group membership.