I agree with your overall message. I also agree with your logic behind the physiological reaction to socialization. And I also agree that people do not spend enough time trying to work with their parrots natural behaviors (I hope I got that across in my earlier comments!). But I don't agree that this kind of covering is not a form of punishment. Positive punishment, most simply defined is the addition of an adverse stimuli to reduce the frequency of a behavior. And we know already that using positive punishments leaves one open to the possibility of negative side effects. So while I think your argument here:
might make sense for some select situations, but certainly does not for others. My problem with covering birds that are obviously screaming for attention is the fact that in many cases the cover does NOT effectively calm them. Especially if (like in the case of the OP) she is merely covering a side of the cage to block the bird's view, but the bird can still hear and understand everything that is going on around it, it could have the opposite effect. In a similar vein, all of my birds are covered to sleep at night. But in the morning, once it gets light out and they can hear me moving around the house making breakfast they will start making a racket. They aren't simple enough to be fooled by the "artificial night". And once they get started they absolutely will work themselves into a frenzy if I don't come uncover them within the next half hour. In both of these cases I believe there is no real stress relief going on. With very short covered periods? Maybe, but again there is always going to be huge variation depending on the situation and bird.
Again I feel like the answer here is probably yes and no. I don't have experience owning the largest parrots so can't say how their emotional attachments differ from the smaller species. But owning my own birds I have yet to notice an "exponential increase" in their desires to be with us the more they are given the change. In fact, I've experienced the opposite. Like I mentioned to the OP, when I spend MORE time at home and give my birds both the freedom to go and do what they want they tend to spend LESS time with me overall. For the past 3 weeks we've been on holiday, and today I have spent a grand total of 15 mins with my p'let on my shoulder, 15 mins sitting with our Senegal at the breakfast table, and zero one-on-one time with our aracari. For the majority of the last 3 hours our p'let has spent his time doing laps around the house/sitting on his kitchen perch chatting, aracari-bro is napping on a java stand 3 feet away, and our Sennie has made her way through another stack of cardboard and pine slats. At any time they have the opportunity to join me on the couch, but they are content as they are and have yet to make a peep in protest.
But during normal work hours this is completely different. As soon as come home I'm tackled by a p'let flying into my face, an aracari hopping onto the other shoulder trying to eat my hair, and a Sennie shrieking to be let out. The next 2 hours are dedicated to cramming in all of the attention I can give to everyone. So in my opinion, for SOME birds at least it's about the quality not the quantity of interaction. 2 hours of interaction can be spread across 8 hours or accomplished all at once. But after that quality time the fids are content with something more "ambient". Though this kind of attention may be inferior it still can stimulate that innate social desire that you have described. Of course that means figuring out just what level of "quality" interaction your bird requires, which can be tough (and which is where I think the OP is seeing her issues).
Finally, when I say that a bird can express their desires in a more enjoyable way, I don't think that this automatically assumes we are "fighting nature". As you mention, it is completely natural for a parrot to vocalize when stressed and isolated. Trying to stifle these vocalizations would be unnatural. Trying to modify them however is not. My favorite example was one I saw at a parrot training workshop hosted by Barbara Heidenreich. She was very adamant in asserting to the audience that vocalizing in parrots is normal and to be expected (after people brought up numerous questions about "excessive" screaming). She never wanted someone to think they could eliminate the behavior but emphasized with her own home video how these vocalizations could be trained to a more positive spectrum. She showed a time lapse video of her own amazon screaming whenever she walked by the cage. Cut forward a few weeks and now he was saying "Hello!" instead. After these positive vocalizations he received the attention he craved. She showed how she was able to prolong the time between true screams by teaching him to instead repeat back all of the phrases or whistle the tunes he had learned instead. He would talk to himself for up to 45 mins before receiving his reward.
Now a person does not have to wait this long before responding to the bird (especially if you think it is stressing them). So instead just respond soon after your bird calls you with the more pleasant vocalization. In the end I see it benefiting both parties. The bird is not encouraging negative emotions in the person and yet still achieving their desired effect.
