Several people have referred me to Mark's blog in the context of paleolithic dieting. I've been going through the archives, and it seems pretty solid. Of course, like many blogs now, it's really half blog, half sales funnel for information products.
(Which is totally cool, but it sometimes overshadows the fact that the blog posts themselves are valuable.)
It's not necessarily a contradiction. Example: we used to get regular doses of minerals from our water supply. Today, we largely filter these minerals to make "hard" water "soft."
Doing what our ancestors did ≠ ingesting what our ancestors ingested. Supplementation can close these sorts of gaps.
The foods our ancestors ate don't exactly exist anymore. Animals are smaller and we eat fewer wild ones. Fruit is sweeter. I'm not big into supplements, but I do recognize it's hard to get the right nutrients even eating paleo.
Mark seems to see the main problem with the carbs contained in grains. This does not apply to Gluten protein obviously, as it is nearly free of carbohydrates. The only problem with Gluten seems to be that some (up to a third according to Mark) people seem to be intolerant to Gluten. From what I could gather from the two links you provided, you should be ok with a Gluten-heavy diet as long as you make sure that you are not sensitive to it (which can be diagnosed easily)
So did Grok (that's how Mark calls the paleolithic human) eat supplements and isn't there a conflict somewhere?