Most fraternities have a federal tax exemption under section 501(c)(7) as social clubs. Longstanding IRS policy is to treat fraternities as social clubs and not as educational institutions under section 501(c)(3). The (c)(7) exemption applies only to "exempt function income"--the dues paid by members as well as charges for goods and services. Other income, including at investment income over $1,000 is taxed.
Since 1976, Section 501(i) of the Internal Revenue Code prohibits an exempt social club from having a charter, governing instrument, or written policy statement providing for discrimination on the basis of race, color, or religion. (A 1980 amendment allowed auxiliaries of religious organizations and the like to restrict membership based on religion in certain circumstances.)
If the racist actions at the Auburn fraternities are in any way based on written policies, then they can and should be stripped of their tax exemptions.
Tim Francis-Wright