Good point. We live in a society where killing animals for food has been "sanitized" away from our consciousness. Perhaps that is a good thing if it makes us a kinder, gentler people as a result, though I haven't seen any real evidence that has helped.
I often give away extra roos to local people who are from different cultures where killing and eating a chicken is a normal event. They prefer to buy a live chicken over a shrink wrapped carcass from the store. I can't control what or how they kill these birds - heck, they could be using them for cock fighting for all I know.
I also hatch chicks and I do end up with male chicks I cannot house. Attempts to give them away has met with limited success, so some are euthanized with CO2. This is quick and easy, and has been approved by government vets who are tasked with making sure the poultry industry is as humane as possible. Their bodies are frozen and given to a friend who raises snakes. Personally, I don't find this difficult or distasteful, but I understand others may. For these chicks, I have a measure of control over their humane treatment that I do not have when I give away (or sell) either chicks or grown roosters. I know for certain that I have sold chicks to well meaning people who were not aware of the wiliness of predators, and the chicks I hatched and sold were terrified, maimed and then killed in the most inhumane way possible. I believe the males I killed with CO2 had more humane treatment than those.
I believe it is up to each of us to make personal judgements in such matters, and it is not my right to judge where someone else draws the line regarding ethical treatment of their birds. There are certainly egregious cases and cruel people - we must do what we can to stop that, but that is not what we are talking about here.