I feel the article is angled towards couples that have been together for a significant amount of time.
I feel most relationships might?? start out hot & heavy.....& enter the then what stage. What happens when you're in the throws of life & sex is pushed to the sidelines.
"Take a chance, even if you're not in the mood," is angled towards putting pressure on the person that has the lower sex drive. This philosophy I feel, turns into an obligation. Sex can then be seen in a longer standing relationship as an obligation to keep the relationship going.
"Knowing that sex WILL occur may help the low desire partner to 'turn themselves on' in preparation..." is another obligation.

I do agree that it is not the only way to show love for a partner, but when it comes down to the nitty gritty my SO wants sex, even if I don't. Even when permission is given to find another, I'm still obligated to having sex for another persons satisfaction. I know that is certainly not how every long term relationship grows, but it's where I find myself.