There was a post on freethoughtblogs that I'm really annoyed I can't find. It made a lot of sense in regards to defending the prejudice + power definition. If I remember correctly, it opined that racism is too strong of a word to refer to simple prejudice. It doesn't make a whole lot of sense when you think about it, either. We don't have specific words to describe prejudice based on anything else, like taste in videogames, clothing, etc. Skin, poverty, or sex shouldn't be any different. Adding an "ism" to refer to harmful policies based on individual prejudices makes much more sense because it offers greater clarity, since racism, sexism, etc have strong connotations. It's not because it's a secret agenda on behalf of academics to make minorities not racist.
When you hear the word "racist" there's a **** ton of imagery that comes with that word, lynchings, separate water fountains, voter intimidation, churches being set on fire, etc. It's too loaded a term to also simply refer to someone having a shitty attitude about you because of your skin. Hence, the need to do away with "institutional racism" and simply have racism alone refer to institutional prejudice based on skin color. Everyone thinks of institutional racism when they hear the word racism anyways, so why not just say racism? Where is the big loss? Under this definition, minorities cannot be, or only very rarely racist. They can still be prejudiced jerks, though. It seems like why this redefinition is being resisted is because white people are fully aware of the immense connotations racism has, and if it's merged institutional racism, they won't have a word to put clearly oppressed minorities on equal footing with them anymore.
And thumping the dictionary in this debate makes you a tool because 1) Language evolves overtime and 2) It's okay to redefine things! Sometimes, we redefine words because the new definitions are useful or have greater explanatory power. There's nothing wrong with it. If redefinitions don't catch on, they don't catch on. The prejudice + power definition may fail, but it's not vaccuous just because it's a redefinition.