A sophomoric attempt to discredit the African-American Museum in DC:
The late Sen. Jesse Helms was an ardent opponent of establishing a Smithsonian museum for African-American history. He argued that it would trigger a string of history museums based on race and culture.
The more likely reason for his opposition is the very strong possibility that he himself would be on exhibit, and not in a position of honor, either. Not only did he adamantly and powerfully oppose civil rights, desegregation, voting rights, affirmative action, etc., he also spent 16 days filibustering the Martin Luther King, Jr. national holiday.
I fear that when we create identity museums we lose historical inclusion, the view that we are one American society no matter our diverse backgrounds.
If by "historical inclusion" you mean being crushingly subsumed by the Eurocentric approach to American history; to be relegated to a single, short chapter or footnote, with the ubiquitous and moderately frightening dagguerotype of John Brown thrown in as proof that "we've always cared"; an occasional special exhibit tucked away nicely in a side-room, so that museum visitors aren't impeded in their quest to view the really important stuff; then yes, maybe we do need to lose some of that historical inclusion.