I am not a medical expert so I can't comment on this beyond what I know from my own investigations - both about ProArgi-9 in particular and supplements and L-arginine in particular.
L-arginine can cause problems when used BY ITSELF - or so I've read - and that's partly why and how Dr Joe came up with this particular combination of vitamins etc., to make sure everything is balanced properly.
I also know that a lot of these problems can be caused because the L-arginine is not pure and there are issues because of it being contaminated by other things during the processing. It's the contaminants that can make people sick and cause the reactions you've read about.
They mention the problem in FDA regulations - this is true - but PA9 goes through something like 267 tests during its production and they use the highest grade, purest L-arginine IN THE WORLD so no contaminants in it, or in any of the other components.
If any one of those tests is not passed, they sell the product to their competitors, as it is not high enough quality for Synergy.
I sold PA9 to a man in his 80s with kidney failure, massive heart problems etc and he took the PA9 to his chemist, who did lots of research and compared it with his meds, and she came back saying it wasn't a problem.
"Dr Joe" has been using four scoops of this stuff every day for many years. He's never been healthier. I'm sure you've seen information about how he was awarded "Father of the Year" in (I think it was 2008) by the American Diabetes Association because at that time, it had been something like 18 years since he'd had a diabetic patient admitted to hospital for any cardiovascular problem. I think it's safe to say he wasn't killing them off with kidney troubles either!
I don't know if you've seen the information on my website (which I completely rebuilt a couple of weeks ago) but there's a bit here - along with a few videos you might find interesting:
http://www.libertyforrest.com/proargi9.html
I had terrible heart trouble for many years. Lots of heart attacks, lived with unstable angina for a long time and was extremely ill. When I was first introduced to PA9 I saw on it that you're not supposed to take it if you've had a heart attack, but this was puzzling, especially when I had seen a long interview with "Dr Joe" in which he said he had been using it for people who were in the middle of heart attacks, and it stopped them and reversed the damage (all this visible on EKG).
I can't advise you medically, of course, but I can tell you that I've never felt better since I've been taking this stuff (about a year) and my heart is much better and stronger than it's been in years. I'm walking four miles in an hour, when I couldn't go five minutes at a leisurely pace before.
I'm sure you could find all kinds of 'negative' information on the internet about every vitamin or mineral out there. You're always going to find conflicting information on ANYTHING you look up.