You might want to take another look. CoH's post , when using 'they', is referring to his doctor and her resident. McM is referring to 'at risk kids' in the plural,...i.e., their experiences. In both instances, the plural rather than the singular. And gender is not relevant to the reference. So...you're the one that's wrong, genius. Get over yourself.
As to the alleged frequent use of 'they' in this context, it is far less frequent, as COH and MCM showed with their examples, than the use of non-gender pronouns relevant to the given situation.