Well, as a research scientist myself (academic, not industrial), I refuse to believe that publication of scientific results is typically motivated by the desire to make money. Yes, it happens; and yes, academic Science is occasionally faked for non-commercial reasons too (e.g., ego, promotions, etc.). But, scientific publication is kinda like democracy-- it's the best system we've got. It is the system that scientists have agreed upon as the best way to communicate their findings. Word-of-mouth and internet forums are just way too inefficient. When a study is published in a well-respected journal, other scientists have the opportunity to repeat the work and confirm or dispute the findings. Logic dictates that very few of the other researchers providing independent confirmation of a seminal study will be in a position to profit financially. And such peer review is really the only way to determine how universal the conclusions are. The Vioxx situation is somewhat different from most-- clinical trials of a new drug require a LOT of money and entail some risk, so it is difficult to find "takers" who will attempt to repeat them.
What I'm really trying to say is that if we give the broccoli researchers the benefit of the doubt-- that is, assume they were motivated only by a desire to help the afflicted-- it would have been counter-productive for them to simply present the results at one small meeting and then never publish it. I assume they either 1) tried to publish it and were rebuked by peer-review or 2) did further research that led them to conclude the initial results were a fluke.
That said, broccoli is indeed a very healthful food! It contains way more vitamin C than citrus and plenty of other good things too. So yes, it could well be one component of a healthier diet, which can only help the average person's immune system.