Etymology Wars Redux

Following the example of historian Gregory Melleuish, Janet Albrechtsen goes the nitpick in an otherwise sensible article in today's Oz:

Twice, Sane Australia wrote to inform me that I used the word "schizophrenic" inappropriately to mean dual nature. This perpetuates the myth of split personality, they said, which has nothing whatsoever to do with schizophrenia. The only problem is the Concise Oxford Dictionary says that "schizophrenic" derives from the Greek skhizt, to split, and phren, the word for mind.

She then goes on to defend her own use of the word schizophrenic (in describing the union movement):

Sane Australia's letter pointed me to Reporting Suicide and Mental Illness: A Resource for Media Professionals, to guide me in my errant way with words. The problem is I was not writing about suicide or mental illness. I wrote about the union movement and used the word "schizophrenic" in its well-understood colloquial sense.

The logic here seems to me a little unhinged; if Janet was using the word in its "well-understood colloquial sense", the etymology, interesting as it might be, is hardly relevant. That "well understood colloquial sense" incidentally is a good example of a "popularised technical term"; HN Fowler covered the subject in Modern English Usage years before anyone invented "political correctness".