Sadly I will not trust most things out of any politicians mouth once they have spent more than a few years in the political arena. Lying just becomes second nature for all of them.
I never said he wrote it, only that he published it...in a magazine that was titled "Ron Paul's Newsletter" with him as the lead editor. Even if he didn't pen the articles, by publishing them under his name there is at the very least an implied agreement with the authors viewpoints. This is why all magazines will have disclaimers at the end of any articles whose view diverges greatly from that of the editors. By publishing it under his name he had a certain responsibility to ensure that the views put forth coincided with his or else he shouldn't be surprised when those views are attributed to him.
Regardless, I would have had a lot more respect for him if hadn't first claimed that the articles were never written, and then when they were dug up claiming that he didn't even know who wrote them.