I always enjoy Left-footer's blog. But I reckon he's worrying too much on Pope Francis's behalf here. I reckon Popes get special training in not getting over-excited about people's feet.
Personally, I had absolutely no lustful feelings about the people whose feet I washed on Maundy Thursday. Although, to be fair, I could barely see their feet. You have to stand well back when you're using a hose.