People need to take responsibility for their own behavior vs having someone else recognise it and protect them from misinformation.
Not everyone is competent.
I used to think seat-belt laws were an infringement of people's rights until I saw the reduction in accidents, suffering, and cost-savings those laws brought about. Now what posesses people to not do up a seatbelt? Is it the urge to thumb their nose at being 'told' what to do by common sense?
People do stupid things that jeapordize their health and most people are unwilling to watch them pay the heavy price in misery and suffering their actions result in. Just because someone gave themselves cancer with smoking I'm not going to advocate withholding cancer treatments. I will however support making it illegal to smoke.
Saying that "people need to take responsibility for their own behavior" is of course the ideal that is never achieved. There are actually very FEW people who are rigourous in their self-analysis to the point they even know "why" they do the things they do let alone able to take responsibilty for their actions.
It just makes sense that we protect the quality of our lives by helping those with no self-control. Unfortunately our current methods have the undesirable side-effect of painting everyone with the same in competent brush. This is where technology should likely be able to help in the future.
I personally feel that there should be some questions that a person should need to answer about the basic action behind supplements including possible negative side-effects before they are allowed to order them. Much like a WHIMIS test. Of course this would cut into the sales somewhat, but if people are ordering them who don't know what they are taking or why, aren't those the people you want to put some controls on?