Good observation/discernment on both counts.
I would still say, though, even though these two variables alone could help explain why Utah would easily crack the "Top 10" list among states, you would expect that two factors would help to offset what you mentioned to pre-empt Utah from claiming #1 state porn subscription status:
#1: What is cited here is porn subscriptions. Subscription-porn is even a more formal commitment ($) to supporting the porn industry than viewing free porn. That's what especially surprises me about Utah. Not only would you expect the 60% state Mormon stats to pre-empt such a #1 rating, you'd expect two-timing porn Mormons to be more covert vs. open tithing to the porn industry.
#2 And that's especially true given that Utah boasts the most number of married-family homes…a % that actually even rose 2% in the past few years. This means Utah culture is marriage-focused in deterring divorce as couples go through their 20s, 30s, 40s and 50s.
Under the surface, it shows a lot more is going on vs. clean-cut image portrayed.
At the same time, the mormons' public face probably encourages more virginity among women, so that's another factor in the porn rate. The churchgoing rate in Utah is only 51 percent, so they can't be held responsible for all "jack Mormons" either.
Curiously enough, the original story was used to smear all conservatives despite there being "little variation in consumption between states." We're talking a difference between 2 per 1,000 and 5 per 1,000.
Catholics like me used to be a lot better at combating indecency, and we only did it because the WASPs stopped upholding standards. Now it seems like the LDS are the only ones left. I'm glad someone at least cares. And maybe the Utah porn rate would be even smaller if the rest of us were better at shunning it.