While true and I get your point, there isn't anything inherently wrong with that. We should expect and welcome research with the awareness of vested interests.
Afterall it's not surprising for a substance to be beneficial in certain ways yet harmful in other ways. Research from opposing groups will help identify all interesting attributes of a substance. Until we learn all there is to learn, you should approach these papers more as additional clues pointing to a certain direction and not anything conclusive about the substance in question.