I agree, but we have to be careful as to not get into the habit of tossing out every study whether its advocacy or not in the hunt for true science, chances are every study has a advocate behind it..the government, special interests, big pharm, etc.
I don't toss out every study that comes along, never have, regardless of it's funding. What I primarily toss out are the "articles" written about the studies, that very often distort exactly what the study actually said. And that distortion is generally where the bias shows up. So before I toss anything I like to at least see the abstract to determine how badly the "articles" have distorted the actual results.