Mucking up the language is a crime against understanding.
Redefining established words is not acceptable.
Anyway, this discussion is a red herring.
Adria just wants an excuse to be racist, and you're defending her.
If twitter isn't suited for "nuanced arguments", well then you shouldn't be using twitter in the first place! Write a blog post and only share the link (and title). It's that simple. It doesn't matter how good something sounds in your head if you can't voice it correctly.
A dictionary only outlines common usage (it does not provide context), and I indicated the common usage in my comment as well. If you ever want to make a nuanced argument, you must clearly define (and sometimes re-define) the words you are using! Otherwise, someone with a dictionary or a thesaurus can quickly distort your intentions by distorting the original meaning outside of its original context.
Take a look at my other response below -- it may clear things up a little, but my point still stands: Adria was not using "racism" the same way you are defining "racism," and just because she did a poor job of explaining her position on Twitter does not automatically invalidate her opinions (it just means her opinions were not adequately explained).
http://en.wikipedia.org/wiki/Racism#Definitions
Or do you accept this definition as superior to one in a Physics textbook? http://dictionary.reference.com/browse/gravity?s=t