Why do physicists prize a role which renounces power or control in the political, economic, or environmental, or social arenas? Certainly the power we physicists have wrested from nature has transformed human affairs in these areas and others, and certainly physics itself is constantly driven from within to obtain more power and control over nature; this is at the center of our mission.
Perhaps what looks on the surface like an abdication of power is actually at the heart a way of obtaining still more power, prestige, and security. Having an esteemed and needed role, and using this role to distinguish and divide themselves from others and their affairs, allows physicists to formalize a social contract with the world at large: society will provide generous funds, liberty, security, and respect, and in return physicists will tend the fountains of progress promising quality of life (power) for all but not asking any questions about how that power will be used. If faith in progress is akin to religion, then physicists might be compared to priests or shamans: people who promise and maybe deliver success and power, but wash their hands of profane things like politics and business, while expecting in return esteem, respect, regular support, and a realm of control.
This social contract between physicists and the larger society allows the two parties to absolve each other of responsibility. As I already sketched, physicists do not take responsibility for the ways that their focus on power has been imitated and continued in the world at large, or even for the moral issues of their own research activities; in other words physicists lay the responsibility with society. But in exchange society often lays the responsibility for its horrors and sins at the doors of science. This can transfer of responsibility can take one of two tracks; the "pessimistic" track attributes our ills to science and technology: some of the keywords are "nuclear", "genetically modified," "organic," "free radicals," "virus," "radiation," "chemical," and "pesticide," but there are many more suspicions ranging from the widely accepted to the fringe. Many of my Italian friends are still convinced that microwave ovens can cause cancer. While the attitude can be one of thoughtful discernment, at times the feeling is more one of terror about particular keywords and of blaming science for the world's problems and for life's insecurities, for instance the various ways we could die. While I believe that the scientific community should take responsibility for the moral weight of its actions, my expectation is that culpability will not center around mysterious technological keywords but instead around issues understandable to everyone like abuse of power and lack of respect.
There is another more "optimistic" way that society transfers the responsibility for its sin and failures onto science: faith in progress. If nuclear materials threaten to poison our world, we rely on our scientists to sooner or later provide a safe disposal technology. If we have poisoned our earth and water and stripped mined our land into lunar landscapes, then some day reprocessing and cleansing technologies will restore them. If the disenfranchised turn to terrorism or illegal migration, our scientists will develop new security technologies and smart bombs. If millions die yearly from wars, malnutrition, malaria, and political difficulties, then we will perfect the science of globalization. If we have an epidemic of obesity or AIDS, then we put people to work on new drugs, surgeries, exercise machines, prophylactics, immunizations, selective abortions, psychiatric and psychological techniques, mass media campaigns, and gene therapies. We can do no wrong as long as we continue giving money to scientists, because the scientists are sure to find a way to right all our wrongs. The "temporary" problems along the way are just the price of progress.
As a particular example, with the modern concern about global warming some people are popularizing the concept of the "carbon footprint," which means that your personal contribution to emission of carbon into the atmosphere. Along with this concept there is an organization which will allow you to pay them instead of reducing your footprint. If you go on an extra flight, that's OK: just give them a little bit more of your money. They promise to use your money to make a compensating reduction in the world's carbon emissions, perhaps by reducing someone else's footprint, or else by investing in technology that sooner or later will reduce emissions. This practice is identical to religious practices of sacrifice and atonement. People take what is precious to them: grain, cattle, money, clothing, in fact anything of value, and give the goods over to priests to either destroy or else devote them for sacred causes. In return for their sacrifices the people lose responsibility for their evils and are promised healing, success, and prosperity. Only two things have changed: (a) we have some new "sins" like pollution and the carbon footprint, and (b) now our priests are called scientists, experts, environmental advocates, etc. The substance is still the same: we give them our money, they give us freedom from any moral qualms about our actions and also a promise of prosperity.
The specific role that physicists cast themselves in allows them to confer moral responsibility to society, and in turn society transfers back its responsibility through faith in progress or else demonization of specific scientific keywords. In this exchange everyone is freed from responsibility, from qualms of conscience - which is another plus for the power seeker. Perhaps one of the greatest benefits which physicists derive from the role they cling to is precisely the way that it frees them to research what they like without moral or human considerations.