Fat is "looser" if I can use that term when it is located closer to the heart. So people who hold a lot of fat around the gut as it is said in the article have more of a chance of the fat deposits located there finding their way into the heart obviously causing negative effects.
Around the thighs it's not as "loose" so it's harder for it to become incorporated into the blood stream and being deposited in and around the heart.
This is just me thinking out loud, but a lot of people with large thighs have them because they use them a lot, as well. Mine are pretty large, but I walk a lot and jog a lot. And they are not all muscle.
Just saying.