If someone doesn’t have the courtesy to think of others if they have a cold then that is sad and indeed inconsiderate of them. But we shake hands outside of Mass all the time and these people may be equally inconsiderate.
Unfortunately, there are some people who are like that, but they don’t think it’s inconsiderate at all. They believe that because they are at mass, there is no way that they could pass on their cold to other people. I’ve met people like that, who have actually related this belief to me. It’s not common, but when I have encountered people like that at a couple masses, I’ve ended up getting a cold and sore throat shortly thereafter and lost a good portion of my income due to having to cancel music performances. They don’t mind shaking hands with other people with colds either. I once had a cold, but was well enough to be at mass although I was still coughing just a little. I sat away from everyone. During the sign of peace one person walked up to me. I politely and softly told him that I had a cold and didn’t want to give it to him. “Oh, I don’t care,” he replied and proceeded to grab and shake my hand then went on to other people shaking their hands and passing my germs to the others. I felt so bad.
Also I believe that someone stated that they don’t like being touched- this seems to stand outside of the issue of illness.
I know that you weren’t meaning to downplay and put down people who don’t like being touched, but I just want to point out that there are legitimate reasons, other than sickness, for people who would not want to be or cannot be touched, due to certain experiences, situations, etc. One example would be an abuse victim. The thought of a stranger - especially of the gender of the abuser, could be too much for that person to make any kind of physical contact. As a person who experienced this myself and knowing others who were in worse abuse situations, I know that this is a real thing. Some of these people may not have gotten to a point either on their own or through therapy where they can handle physical contact. I mean, they really can’t say, “I’m sorry, I can’t shake your hand. I was sexually abused by my uncle and you look like him. The thought of being touched by you brings back horrible memories.” Yes, they can eventually get through this period and may be able to handle physical contact in the future, but until that time, we can’t tell those people to just suck it up and shake that man’s hand. You especially can’t say that to a child or teenager who are either currently going through the abuse or are trying to deal with the past abuse on their own because even their own parents had no idea that their brother abuse their own child.
There could also be people who are xenophobic or have other kinds of phobias which keep them from wanting to have physical contact not just with strangers, but even with people they know.
Then there are just people who don’t believe in doing the sign of peace, feeling that it takes away from the mass. I have friends who will not do it at all. They will kneel and pray or just close their eyes and pray while it is happening. I’m not turned off by it or think it’s inconsiderate. I respect it and know it is part of their spiritual journey.
Anyway, they are just things I remind myself of when there are people who don’t want to do a physical sign of peace.