It's not true just because I said so. It's true because (a) it's the only meaning that makes any sense whatsoever in the context of a single stat (salary in our case), and (b) because that's how it's used, regardless of whether you find it philosophically objectionable.
Mean vs median can make a huge difference.
http://en.wikipedia.org/wiki/Househo...es#Mean_income
"Overall, the mean household income in the United States, according to the US Census Bureau 2004 Economic Survey, was $60,528, or $17,210 (39.73%) higher than the median household income."
And no, mean is never the right stat to consider in politics. Mean is about the few top-paid people, median is about the many less-paid people. And in politics, the many is more important than the few. There's a reason you phrased your point the way you did it - what the "average" guy earns is what matters, and mean simply does not measure that.
Now, in the case of New Jersey teaching salaries, the difference probably will be well under 40% because the range of salaries will be smaller. But the fact is you falsely quoted a stat at the beginning of your post, and then when called on it, you blew smoke and still haven't admitted your mistake. If you can't back down even where you are flat-out wrong, why should I or anyone else believe anything you have to say?
If you think it's ridiculous, you have no idea what it's like to be a high school teacher.