"Derailing for dummies" is an interesting analysis of this. It should be required reading for participants of discrimination-related discussions.
The only purpose is to create a rhetorical Escape Hatch [1] when logical arguments fail (or one is too lazy to construct them).
[1] http://rationalwiki.org/wiki/Escape_hatch
"Derailing for dummies" is an interesting analysis of this. It should be required reading for participants of discrimination-related discussions.