So what’s in the Finley Times Style Manual? 
When the minority gender in any given occupation is below 20%, use the majority gender only and pooh-pooh people who violate this rule. When the minority reaches 20%, use the majority gender, don’t pooh-pooh those who use “he or she”, but do pooh-pooh those who use the minority gender. When the minority reaches 40%, use either gender and don’t pooh-pooh anyone. Is that about right?
It doesn’t matter if female coal miners exist; any reader, male or female, will have an image of a coal miner in his or her head, viz., a large male with a flat cap. Writing ‘she’ scribbles all over that image with a black marker and makes the reader construct a new one.
I remember my classmates and me laughing our heads off at the phrase cave people (as opposed to cave men) as recently as the 1990’s. Now itsounds completely normal to me. Dominant ideas change.
How many keys have you hit explaining why you don’t want to hit many keys? 
Americans speak English is generally true but doesn’t come close to telling the whole story. The fact that it doesn’t tell the whole story doesn’t make it untrue, just as your generic male coal miners are not unreasonable, but the fact that it’s not untrue doesn’t make various languages are spoken in America untrue, and similarly coal miners are not all men happens to be true.
For me it doesn’t. There are female coal miners, period. There are male nurses, period. These are objective facts. Liberation is a state of mind.
Highlighted the key word. 
Returning to the no-arms-and-legs example, I hope you’ll accept that that is unequivocally a genetic mistake. Anyone born with this condition has a big problem. I don’t think many people would be unkind enough to suggest they should be quietly put down for the good of the species; they often turn out to be very inspirational people. OTOH one would not be very inspirational if one spent the rest of one’s life whining and moaning, even though you’d have massive justification for doing so. Sometimes life sucks, and it sucks for some people more than others.
I take it you’re not into the triple helix theory.
Not at all! The era of celebrity babies predates Andy, and it hasn’t ended.
I mean the overall pool, for basically everyone. Of course not everyone has convenient access to the entire human population, especially as upward socioeconomic mobility keeps decreasing (compared to half a century ago), but the average human’s geographical mobility has never been greater, and long distance communication has never been easier/faster/cheaper. Also, the world has never come closer to having a common language than it is now.
I think your perception of humanity is based more on your own experience and whatever locker room talk (or “pub talk” shall we say) was common when you were growing up than on the last few decades of sexological research.
To put it plainly, I think there are way more Milkers and Rockets and what not out there than you realize. But I’ll let people (and cows and raccoons and what not) speak for themselves.
That sounds like something a Tralfamadorian might have said before the enlightening experience of meeting that odd human couple. 
Sorry to hear that he or she is such a trespass upon your right to exist that it makes you wish a chai latte upon me, or something. 
I think it was something to do with the definitions of “normal” and “mistakes”.
