The protesters were part of sizeable chunk of Americans that thought the Apollo missions' $24.5 billion budget should go toward improving life for people on Earth instead of sending men to the moon.
In a Harris poll six months before Apollo 11, only 39% of Americans supported the efforts to put someone on the moon. In the same poll, just under 41% of Americans said they would choose to cut funding to the space program above any other government activities. (For comparison, 18% of people wanted to cut Vietnam War funding.)
The DC protest was led by Reverend Ralph Abernathy, one of Martin Luther King, Jr.'s closest aides, according to History.com. They brought mules and a wooden wagon to juxtapose images of poverty with the gleam of the Saturn V rocket.