This is the, "I've suffered, too." response. It does not negate either the person's unique life experience nor the existence of institutional racism.
Whining about people who say the meritocracy is a myth doesn't make it any less true. Just because people have succeeded despite difficult circumstances means neither that the meritocracy myth is not true nor that others who have put forth equal effort haven't failed.
True, life is unequal and unfair, but it's more unequal and more unfair for others simply because of their race.