The fact that you never heard of him is not the same as "we've heard zilch about John Lewis". He was certainly known by those with even a thin knowledge of the 1960s civil rights movement prior to this incident.

http://baltimorepostexaminer.com/john-lewis-honored-u-s-holocaust-museum/2016/05/05#sthash.J9c9UBIy.dpbs

http://www.achievement.org/achiever/congressman-john-r-lewis/

And there are countless photos from the 1960s in which Mr. Lewis is a key figure.