A vocal group gathered outside the NFL’s head office in New York last week to support free-agent quarterback Colin Kaepernick.

The harmless event was meant to express to the league that fans are dismayed with Kaepernick’s unsigned status, but it’s unlikely it made much of an impression on one of New York’s NFL teams.

New York Giants co-owner John Mara said Kaepernick’s protest of racial injustice during the 2016 season led to a flood of mail from his fan base. After Kaepernick took a knee during the national anthem, a large number of Giants fans responded with disgust.

“All my years being in the league, I never received more emotional mail from people than I did about that issue,” Mara said to Jenny Vrentas of The MMQB.

“‘If any of your players ever do that, we are never coming to another Giants game,'” Mara said of the notes. “It wasn’t one or two letters. It was a lot. It’s an emotional, emotional issue for a lot of people, more so than any other issue I’ve run into.”

After the season, Kaepernick opted out of his contract with the San Francisco 49ers to test free agency.

He will reportedly stand for the national anthem going forward.

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