Honestly, I don’t think that was the main point of the article, especially if you look at the charts. I saw Catholic denominations in there I’ve never heard of before. This appears to be aimed more at the idea of people who support gay marriage taking the Bible out of context and deciding for themselves that it’s ok.
I think you’re right, that’s the author’s (intended) point but he fails miserably. The two graphs are conflicting as far as I can tell, and they are even in the same year from the same poll. Something stinks, like stale French fries.
As best as I can figure the second graph represents a greater breakdown of both Protestant groups and Catholic ones, as well as independent Christian groups. I really can’t tell though. Maybe I’m missing something.