Players' union bosses praised Burnley captain Ben Mee's reaction to a "White Lives Matter" banner flown over the Etihad Stadium, as anti-racism campaigners said change was unstoppable.
A banner reading "White Lives Matter Burnley" was towed by a plane shortly after all players and match officials had taken a knee in solidarity with the Black Lives Matter movement on Monday.
Mee, in his post-match comments after his side's 5-0 defeat by Manchester City, said he was "ashamed", urging people to "come into the 21st century".
In a statement, Burnley promised to hand lifetime bans to those responsible.
Iffy Onuora, an equalities officer for the Professional Footballers' Association, said the Burnley skipper's strong words had been well-chosen.
"You get that moment of deflation but then there's the positive reaction since," he said.
"I thought Ben Mee was absolutely fantastic. You feel inspired again. These are uncomfortable conversations but in order to progress, you have to have them."
The words "Black Lives Matter" have been printed on the back of shirts in place of players' names for the first 12 games of the Premier League's return.
Players, coaches and referees have taken a knee before kick-off in every match to show their support for the fight against racial injustice following the death of George Floyd in the United States last month.
"In itself, the words themselves aren't offensive, it's the context," said Onuora, a former head coach of the Ethiopia national side, referring to the banner.
"It's the rejection of conversations we are having at the moment and that's what it represents."
Sanjay Bhandari, chairman of Kick It Out, English football's anti-racism charity, said the fans who had organized the stunt were missing the point.
"The point of Black Lives Matter is not to diminish the importance of other people's lives," he said.
"It is to highlight that black people are being denied certain human rights simply by virtue of the colour of their skin. It is about equality."
Piara Powar, executive director of anti-discrimination body Football Against Racism in Europe (FARE), said those flying the banner were fighting a losing battle as momentum for change was unstoppable.
"Set against the BLM message of equal rights, 'White Lives Matter' can only be motivated by racism and a denial of equal rights," he said.
"It shows exactly why the fight for equality is so important and why the majority of people have supported it.
"The movement, the issues that are being discussed and the change that will arise is unstoppable. History will judge that this was a moment that led to change."