I can't speak for all "greenies", but as for me...
Growing up, I was taught that my feelings and concerns didn't matter to anyone but me, except insofar as someone else could get something out of it. For example, imagine a selfish, narcissistic mother whose behavior alternates between indifference and hostility towards her child... except for when outsiders to the family (neighbors, for instance) are watching, and then of course, she plays like she's mother of the year and just cares soooooooooo much.
And when the neighbors have gone away again, she co-opts the child to listen to listen to her ***** about stupid, trashy, and clueless the neighbors are (yes, the same ones she pretended to be so warm and friendly with just a bit ago), and then it is right back to treating the child with alternating indifference/hostility. And later, when the child encounters the neighbors, they gush to the child about what a wonderful person the child's mom is...
What conclusion is that little child prone to draw, regarding life and the nature of affection?
1) Emotional intimacy is a lie.
2) Deep down, nobody actually cares about anybody but themselves.
3) Nobody actually has your best interests in mind but you.
4) It is useful to pretend to care about others sometimes, because it makes people more prone to think well of you, to believe you, and do what you want them to.
5) Only a fool trusts others. If you tell people things about yourself, they'll just use whatever you said against you later.
I was that little child.
It even bleeds into my understanding of friendship. Bear in mind, I have the same social needs as any other human, although I vent most of that online and suppress it otherwise. The reason why I suppress it RL is because in my experience of real life friendship, it basically consists of the following:
1) Repetitively engaging in activities that you find uninteresting and generally lame (watching movies, going to haunted houses, wandering around the mall for hours on end, etc.) just so you can hang around with people for awhile.
2) Repetitively engaging in long conversations about things you find uninteresting and generally lame (celebrity news, gossip, health nut eating habits, interior decorating trends, etc.), just so you can talk to people for awhile.
3) Getting asked for favors, but there is often little if any reciprocity. Even if you do favors for others, something mysteriously always "comes up" whenever you need a favor in return, or they do it, but whine, moan, and attempt to guilt trip you later to where you wish you hadn't even asked.
4) Telling people whatever "feel-good" stuff they want to hear instead of the truth, because you know from experience that if you tell it like it is, people will drop you.
And the internal result?
1) Boredom, steadily increasing resentment.
2) Boredom, steadily increasing resentment.
3) Anger, feelings of resentment, a steadily growing flame of contempt for their apparent lack of morals re: give and take.
4) Feel like I have a 'no win' choice between being a dishonest slime, and being alone.
As concerns rl friendship, this is why my attitude is basically, "Screw it."
Like I said, I can't speak for all greenies. But this is how the world looks, out of my eyes.