Pope Francis is washing a mother's feet in the photo who is also holding a baby.
Why would anyone have a problem with that?
In Jesus's time a host would wash his guest's feet as a sign of hospitality because the guest would have traveled a long way on dusty roads.
Today, all of those people don't really need their feet washed - Francis is symbolically extending a Christ-like hospitality. That's all.
I dunno, maybe because the rubrics of the liturgy specify viri ("men", as in "adult male humans," not homines, human beings of unspecified gender), and when the chief executive ignores the rulebook and does his own thing (Barack Hussein Obama, call your office), it sets a bad example?
The persons whose feet are being washed are supposed to represent the Apostles, not generic "people in need". The Apostles were all men, and the fact that the Apostles were all men is usually cited as part of the rationale for an all-male priesthood.
“Why would anyone have a problem with that?”