After having read the article, he tries hard to mention that he's making generalizations throughout and that they are not true of every male or female child.
Fair enough...these are stereotypes/generalizations and we should take them as such.
I'm not sure how that's helpful advice for gaming with kids though. Better would have been to list, say, 4-6 "player types" and, if he wanted to cover gender at all, mention if a given player type is more likely to be male or female.
If WotC wants to tackle gender issues, or gaming with children, I'd think that they'd seek out someone who actually knows something about gender issues or children beyond just their own observations. I'd be interested to read an article from a child psychologist, particularly focusing on what concepts in gaming children can understand at different ages (my son is 5).
Am I outraged? Not at all. I don't even think that WotC should do background checks on their writers. I'm actually pretty impressed that when it came out how the writer was pretty myogynistic on his google blog that they pulled the article. Kudos WotC!