Today I came across this excellent editorial by Seth Shostak, a researcher at the SETI Institute, about how many of the most vocal proponents of alien visitations seem to prefer uncivilized arguments to rational discussion on the issue.
Note that some scientists are guilty of the same thing, and most believers in UFOs don't engage in this behaviour. But it is disheartening for those of us who do make good faith efforts to discuss issues to be unfairly attacked.
This sort of uncivil discourse seems to be pervasive in society, and always has been. It doesn't matter whether the topic is science or religion or politics or sports. But that doesn't make it acceptable, and it certainly does not help to win people over to a cause or an opinion.