An iconic image of protest gets its backstory explored in The Stand, Tom Ratcliffe and Becky Paige's look at two Black Olympians who raised their fists and bowed their heads at the 1968 Mexico City games. Reminding viewers that Colin Kaepernick was far from the first athlete to be told he should keep his principles off the field, the straightforward but welcome doc doesn't need to spell out how many of its protagonists' concerns remain pressing today.