San Francisco 49ers quarterback Colin Kaepernick (7, bottom middle) kneels during the national anthem before a preseason game this week against the San Diego Chargers at Qualcomm Stadium. (Jake Roth/Reuters)

To represent the poor, they wore no shoes. To remind of violence against people of color, they sported African beads. To support the “Olympic Project for Human Rights,” they fastened white buttons that said so over the USA logo on the chest of their blue jackets.

But all anyone wanted to talk about that night at the Mexico City Summer Games in 1968 was that Tommie Smith and John Carlos, black U.S. Olympic medal-winning sprinters, didn’t stand properly — with heads held high, and hands over heart — for a rendition of the national anthem. Instead, they punctuated the dark sky with black-gloved fists and lowered their heads in shame for what roiled then in America’s belly, police brutality against people of color who were responding to it with rebellion.

What Smith and Carlos did was exercise the audacity to disrupt a sporting event — which we have been conditioned to believe is a societal safe space, a theater of escape, a spectacle sanitized of any of our ills — with a political declaration.

Nearly half a century later, with the kickoff of this football season, San Francisco 49ers quarterback Colin Kaepernick reminded us of how absurdly we still regard sporting events and their nationalistic rituals. He sat during three playings of the national anthem. He kneeled for another. He did so, he explained effusively, because he felt uncomfortable honoring the symbol of a country “that oppresses black people and people of color.”

Like Smith and Carlos before him, Kaepernick, whose father is black, categorized his concerns. They echoed those of Smith and Carlos and the mission statement of our 21st century civil rights movement, #BlackLivesMatter.

And just like in 1968, it wasn’t Kaepernick’s message that drew so much reaction; it was his method for dissemination. For he dared to protest in the athletic arena, where we wrap sporting events in a prophylactic of patriotism used to demand political conformity and suppress discourse.

As sociologist Harry Edwards, who organized the group that birthed Smith’s and Carlos’s protest, reminded in his seminal 1973 text, Sociology of Sport: “Sport derives its root from ‘disport,’ meaning to divert oneself . . . by participating in the mirth and whimsy of frolic.”

That may be fine for the ruling class that created sport and controls it — and for many among my vocation who publicize it — mostly for profit. But for modern-day athletes of color, like Smith, Carlos and Kaepernick, and others historically marginalized by society, like women and religious minorities, sport is not just fun and games. It is so much more. We were reminded of that in the early 1960s when Muhammad Ali reversed the self-emasculation, in particular, that the black athlete had agreed to in the 1930s and 1940s (and are oddly celebrated as national heroes for doing so) simply to participate.

For those often disenfranchised in society, our games are the most visible space — an exalted space, a space from which most cannot turn away — to voice concern. They create a space in which those who feel that they are not being heard can be heard loud and clear.

Baseball became a place where star Carlos Delgado, a native of Puerto Rico, could bring attention to the Navy’s use of the Puerto Rican island of Vieques as a weapons testing ground, which Delgado and millions of his countrymen opposed, during the run-up to the Iraq War. Delgado protested in 2004 by refusing to rise from the dugout for the seventh-inning singing of “God Bless America.”

It was a place where basketball star Mahmoud Abdul-Rauf in 1996 stopped joining his Denver Nuggets teammates on the sideline until after “The Star-Spangled Banner” ended because he saw the anthem and flag as symbols of this country’s history of oppression here and abroad.

Sport was a place where one-time University of Virginia basketball star Olden Polynice in the midst of his NBA career could bring attention to the plight of his fellow Haitian immigrants being held and deported by this country in 1994. He went on a hunger strike midseason.

But there is no sport that provides as large and gaudy a platform as Kaepernick’s endeavor, football, which over the years has grown into a mammoth business bringing in tens of billions of dollars while being cloaked and marketed in more patriotic imagery than any other games. There are military flyovers. Every game includes a presentation of the colors featuring the branches of the military.

The conflation of football and nationalism is so perverted that the NFL earlier this year said it was returning more than $700,000 of taxpayers’ money that was paid to 17 teams to put on military tributes. Sens. Jeff Flake and John McCain uncovered the “paid patriotism” program, as it became known, in an audit of defense department marketing agreements.

Even the meteoric rise of Baltimore-based athletic clothing manufacture Under Armour can be tied in part to its Freedom line, which decks out college teams like my alma mater, Northwestern, and the university at which I teach, Maryland, in uniforms with designs that harken to the battlefield.

So for me, it is invigorating to see Kaepernick, LeBron James, Dwyane Wade, Maya Moore and a few other athletes with access to that stage not just allow themselves to be used by it. It is empowering to see them appropriate it for those from the communities from which they came whose voices are muted by lack of money, the power it grants and access.

The narrative of sport as a catapult for an athlete from a lower economic class to a higher one, which those of us in the media regurgitate from those who control sport, isn’t just trite; it is dangerous. For it suggests that the most attainable change that can come from sports is for the individual and not a group.

But if sport is also a boost for societal and political change, as has been touted most prominently by the story of Jackie Robinson (the part where he turns the other cheek to racial slights rather than confronts it head-on as he did in the army), then what Kaepernick is saying is to be listened to rather than ignored.

Kevin B. Blackistone, ESPN panelist and visiting professor at the Philip Merrill College of Journalism at the University of Maryland, writes sports commentary for the Post.