Most research in the USA is funded by public money, various DOE, DARPA, NIH, etc grants. In addition, any useful outcome of the research, as in patents or other intellectual property is essentially given to the researcher. As a result, it seems like not only a responsibility, but good policy for the researcher to be able to explain what he is doing to the layman.
It is much easier to get funding dollars for something that the average person and politicians can understand vs. what they can't.