Town youngster Idris El Mizouni said he was "appalled" when home fans at his loan club Cambridge United booed players taking the knee.
Tunisian international El Mizouni, 20, said he was embarrassed by the decision of a number of fans who booed the act at kick-off against Colchester, which aims to stand against racism and discrimination of all forms.
In a tweet, also posted word-for-word by other Cambridge players, the midfielder said: "Appalled and embarrassed by the section of fans who booed us players taking the knee tonight, it’s 2020 and the action is a symbol of solidarity!
"I want to thank the fans who overhauled the boos with applause but this cannot continue."
Cambridge head coach Mark Bonner said the club will continue to support the movement for equality, adding: "It's embarrassing, unacceptable and we don't stand for that."
The boos come after a similar incident happened at opponents Colchester earlier this month, which led to club chairman Robbie Cowling saying fans who boo the gesture are not welcome at his club.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules here