That's an ad hominem argument write large. You can't dismiss a study just because it was funded by someone you disagree with. You have to take it on its own terms. If the study is flawed, show the flaws, if not, it shouldn't matter who funded it.

Funding, like all procedures and data used in the study is very relevant. In a perfect world it wouldn't, but sadly who is paying the bills often dictates the results of these studies. In that perfect world, there would also be scores of scientists who are paid to analyze studies like this to prove/disapprove the conclusion, but again our imperfect system means funding for intelligent study of Marijuana is severely lacking.

I would imagine getting US government funds to study the "potential damage of marijuana on x" would be a lot easier than getting funding for the "potential benefits of marijuana on y".

Just because we don't see competing studies does not mean the data is not there.

If the data is there, show it. I'm open. I think that the 'drug war' is a total waste of time and money, and that having one fewer red-herring for the police to chase around can only be a good thing.

But you can't dismiss a study just because it was funded by biased people. All people are biased. It's up to you to attempt to look past the bias to see what is genuine, and to see to it that your own viewpoint is expressed.

There are plenty of well funded liberal and libertarian groups that would be more than willing to fund the kind of research that you want. In fact I've seen stuff by Cato that would be right up your ally. You'll do far more good by finding this stuff than by criticizing the only studies being presented.