you haven't addressed the issue of having a couple of spare seats beside you on the plane and the ability to stretch out... or are we not allowed to do that because our feet are on the seat?
Yes I have. I answered that before you even asked it. If you do a search you will find a post from me where I've said sleeping on seats is not an issue, but when I've done that, I don't have my feet on the seat, they're hanging off the front.
And as MEL_Traveller already pointed out, several of us have already addressed the issue of feet on walls in homes ...
Really? MEL_Traveller stated that his furniture was not conducive to placing feet on walls and you specifically said you wouldn't do it at home, or as a guest in another's home, but you're fine with doing it in an plane. If the issue has been addressed, it's in vivid support of my observations.
You claim the majority of travelers wouldn't put their feet on the bulkhead ...
Don't take my word for it. It's an observation any of us can easily do. I'll even be more definitive and state the majority of people in a bulkhead row do not place their feet up on the bulkhead. Those that do are definitely in the minority.
putting clean feet on a plastic bulkhead - which is neither illegal nor has any effect on people around you ... Feet on a bulkhead is nothing like feet on a tray table or arm rest - you don't eat off the bulk head ... In fact, someone having their feet on a bulk head doesn't affect anyone else in the slightest ... putting your feet up isn't "disrespecting someone's property" - it doesn't hurt the property either.
You seem transfixed with arguing a reason ... legality, hygiene, comfort, not affecting anyone ... however you are missing some points. You (and others) have placed conditions around your "acceptable" solution, that being to wear nice clean, non-smelly fluffy white socks (OK, I know I added a bit more), and to you that's acceptable. Trouble is, those conditions are not being adhered to by many portrayed in the plethora of pictures that adorn the net. So you're OK, but they're heathens, right? No. The reality is that all the pics and posts across the net, indicate that to the majority of travellers it is not the accepted social norm, no matter how hard you attempt to justify it.
It has ZERO effect on anyone else, which I was brought up to understand is the essence of good manners.
Having ZERO effect on anyone is certainly not the basis of social etiquette. Failing to use cutlery to eat, speaking with a full mouth of food, wearing clothes with obscene logos, picking a nose, slurping the very last drop out of a glass, speaking over the top of someone, etc etc are all socially unacceptable antics which has ZERO effect on anyone else, but whether any of us like it or not, we are all judged by these social indicators.
I'm not sure instruction on the correct etiquette pertaining to the occupancy of a bulkhead and/or reclining seat on an airliner is part of the upbringing of a typical child. In fact I would say accepted norms of behavior are rather subjective in general. I would think it is up to the airline to implement regulations dictating what is and isn't acceptable on their aircraft. That way if those regulations don't meet our personal subjective judgements we may travel with an airline whose does.
It's not all that subjective. Children, in general, are brought up to behave in a manner befitting their environment. An airline bulkhead is no different to a wall in a home and I'm confident the vast majority of children (some medical conditions excluded) know whether they should or shouldn't place feet on walls by the time they are about three. An airline can by all means introduce expectations about behaviour aboard their facilities, but that is different to what's being discussed, that being how the general mass view social norms. It was interesting to watch the QF experiment about acceptable footwear choices in some of their lounges. When it happened, the vocal minority ranted and raved about how draconian QF were and how they would not fly them. Now, just a short time later, the fanfare and outrage of those minority has petered and a recent post on this thread actually made the point that most now simply comply. The simple facts are that an establishment can enforce dress rules (nightclubs, lounge bars and clubs have done so since Adam was a boy) and the vast majority of patrons have no issue about compliance. The few who think they're being aggrieved are the ones that then need to make the decision to forego that business or swallow their pride and comply with what's asked of them.
Quite often when sitting like that I am tall enough that my soles of my feet do rest against the bulkhead. Acceptable or not?
Many bulkheads have a kick zone. Kitchens have kick zones, cupboards have kick zones, hang VA have even included a foot recess in row 3. The lines aren't blurred. If feet are placed up on a bulkhead, they're outside the kick zone, if feet are touching the bulkhead when resting on a place designed for such, they're fine. Even the pic you posted up has a kick zone and it is designed to do exactly as the pax is doing.