1. The article linked to, as I said, expresses my own views on supplementation. The study referred to is peer-reviewed.
2. There's every point in referencing such a study. The participants were taking multivitamins as well as various minerals. Multivtamins include vitamin C. Clearly, most people who take vitamin C don't just take vitamin C, because they buy into the whole vitamin supplementation argument.
3. The whole 'athletes need more vitamins' argument is largely a mechanism to sell more vitamins. Vitamins support various metabolic processes, and it's really hard to think of one that is going to necessitate an intake of many times what a sedentary person needs.
4. The Cochrane review shows a modest effect of vitamin C (based on a relatively low number of studies) on colds in runners, skiers etc, which you've extrapolated to recreational weight-trainers. But OK, fair enough, that's reasonable. Now weigh that against the emerging body of evidence (referenced elsewhere on MAB) that active supplementation with vit C reduces recovery. That vitamin C interacts with huge numbers of other processes, such as processing of iron, which may well bring about deleterious effects. That in some people it's linked to formation of kidney stones. Add in the increased mortality from vitamin supplementation shown in some big trials (remembering that typically people don't supplement individual vitamins).
5. To address your fear that a blanket statement about vitamins fails to take into account all possible cases, I'll add this:
"If you're pregnant, you should probably supplement with folate.
If you have zero understanding of nutrition, and you haven't absorbed the messages about eating a balanced diet that you've been bombarded with since you were five, and you're eating no fruit and vegetables, and yet you've somehow found your way onto a weightlifting site, then you would benefit from changing your diet. If you really can't change your diet for some reason, then you might want to consider multivitamins. If you're a contest bodybuilder cutting for a contest and eating a highly restricted diet, again you might want to consider them.
Before you do so, you may want to talk to someone with formal training in the subject, instead of scarfing them down like smarties in the belief that they are completely harmless compounds and that more is always better."
Powerlifts: 500/363/573 @ 220 belt only
front squat: 403
dips: bodyweight + 176 x 4
military press: 232