There is a 20,000 person 2x2 randomized controlled trial underway right now looking at how useful fish oil is in preventing disease: http://www.vitalstudy.org Results will be out around 2017-2020.
An observational study from the 1970s and a critique of an observational study from the 1970s will carry little merit compared to a 20k RCT.
Knowing that we'll have better data in 5 years, the comment by the researcher is nauseating: "They simply don't do anything for you. The people should know that it doesn't help to prevent heart disease." Since we haven't quite reached an apex in research in fish oil, the comment is short-sighted and is overstating what we know about fish oil to date.