The long-established association of the Maundy Thurday foot washing service with our Lord's washing of His Apostles' feet in the Upper Room before His Passion has been turned on its head in recent times by the practice of opening up the rite to women, Middle Eastern refugees, including Copts, Muslims, and most recently, a Hindu.
Whatever the rite may now be intended to signify -- humility, a servant spirit, a spirit of ecumenism and inter-religious amicability, or, as some have suggested, a theologically-indifferentist politicizing of the rite -- there is little doubt that the Catholic faithful (as well as the watching world) may be scratching their heads and wondering exactly what all this is intended to mean. What does it mean to the Muslim? the Hindu? to Bill Mauer? What does it mean to Pope Francis? I wonder.
What it means to traditional Catholics is not hard to guess. For a good round table discussion of the issue (with five panelists), see the latest Download discussion from March 23, 2016 - Foot Washing (Church Militant, March 23, 2016). They offer a great historical survey and fair-minded discussion of the issue.