IMO colds are not a major public health problem hazard. Most people get at least one URTI every year and most are OK with or without any treatment. There is no vaccine that prevents colds so good hygiene and common sense are needed to limit the spread of the infection. If someone has a cold and insists on kissing a baby then they are very irresponsible and sending your children to school when they are sick with a heavy cold is also irresponsible.
Why talk about colds? To compare peoples' behaviour in other contexts. There are diseases with much more serious consequences than the common cold. Polio, TB, smallpox, yellow fever, whooping cough, German measles, tetanus, to name but a few. All of them have vaccines that have a long history and are proven to be effective. Any side effects or contra-indications are well known by now. Most people tolerate them but a small percentage of people are unable to be immunised. Babies cannot be immunised until around 6 months and must rely on the residual immunisation of the mother for protection. That is if she is immune in the first place.
If people cannot be vaccinated, or choose not to, then hygiene and isolation are terribly important. I was in Beijing during the SARS epidemic and the only defence available was absolute cleanliness. Frequent hand washing with soap was a must as was the continual wiping over of every surface that people might touch. Handrails were being cleaned by women wearing maskes everywhere we went. People who were sick with SARS were isolated and their families quarantined.
I believe we have to think not only about our own health but have a responsibility to try not to infect others. I may maintain the most scrupulous cleaning regime in my home but unless everyone else does the same and the public spaces are equally hygienic, my efforts are less effective than I would have hoped. It is the same with immunisation. I may have a strong immune system thanks to DNA, vaccinations or lifestyle but dangerous diseases will still be around and will break out as epidemics if there are a significant number of susceptible people and if public hygiene is less than optimal. A disease can be controlled or locally eradicated if everyone who can be vaccinated is vaccinated. The figure is around 97% of the population. Before vaccines, even with strict quarantining, diseases ravaged until they burnt out, leaving behind the dead and those strong enough to survive. Those lucky survivors had acquired immunity the hard way.
Having reread my post, I'm not sure I have made myself clear. Let me just say that I think immunisation programs are very beneficial to public health. Without them we would be taken back to the 1700's with much lower longevity. Child mortality would be quite high. Every mother could expect to lose one or two of her children at the very least.