Castleford Tigers have been fined £40,000 by the Rugby Football League after fans shouted homophobic abuse at Crusaders' Gareth Thomas.
Thomas, 35, announced in December 2009 that he was gay.
"The RFL finds homosexual abuse unacceptable, which is reflected in the size of the fine," RFL spokesman John Ledger told BBC Sport.
Castleford chief executive Richard Wright said he was "shocked" by the decision, adding the club will appeal.
"The evidence does not support the decision and does not in any way support the scale of the penalty. We totally refute the outcome of the hearing," stated Wright, whose club have had half the fine suspended until the end of 2011.
Thomas, who has captained Wales and the British and Irish Lions rugby union sides, was subjected to the abuse during the Crusaders' visit to The Jungle in the Super League on March 26.
Castleford's legal advisor, Rod Findlay added: "The club condemns any person who makes or chants obscene remarks towards players or officials.
"But the charges against the club are not that there was chanting, they are that the club failed to take its best endeavours to prevent or stop any chanting.
Our sport is viewed by Stonewall as a model with the way it deals with issues around homosexuality
RFL spokesman John Ledger
"This the club refutes totally. The club has a well-established system for dealing with chanting and could not have done any more on the day."
Castleford will receive a full written judgement before the end of the week and have until 14 July to appeal.
The RFL has stressed that it has taken more steps than any other governing body to crack down on homophobia having joined forces with gay rights charity Stonewall.
"Our sport is viewed by Stonewall as a model with the way it deals with issues around homosexuality," stated Ledger.
"In March 2009 we signed the Stonewall Charter to show our commitment towards these issues. The RFL is the only national governing body to have joined the Stonewall diversity programme which raises awareness over diversity issues.
"All RFL staff undertake a mandatory equality and diversity training programme," he added.
Thomas, 35, announced in December 2009 that he was gay.
"The RFL finds homosexual abuse unacceptable, which is reflected in the size of the fine," RFL spokesman John Ledger told BBC Sport.
Castleford chief executive Richard Wright said he was "shocked" by the decision, adding the club will appeal.
"The evidence does not support the decision and does not in any way support the scale of the penalty. We totally refute the outcome of the hearing," stated Wright, whose club have had half the fine suspended until the end of 2011.
Thomas, who has captained Wales and the British and Irish Lions rugby union sides, was subjected to the abuse during the Crusaders' visit to The Jungle in the Super League on March 26.
Castleford's legal advisor, Rod Findlay added: "The club condemns any person who makes or chants obscene remarks towards players or officials.
"But the charges against the club are not that there was chanting, they are that the club failed to take its best endeavours to prevent or stop any chanting.
Our sport is viewed by Stonewall as a model with the way it deals with issues around homosexuality
RFL spokesman John Ledger
"This the club refutes totally. The club has a well-established system for dealing with chanting and could not have done any more on the day."
Castleford will receive a full written judgement before the end of the week and have until 14 July to appeal.
The RFL has stressed that it has taken more steps than any other governing body to crack down on homophobia having joined forces with gay rights charity Stonewall.
"Our sport is viewed by Stonewall as a model with the way it deals with issues around homosexuality," stated Ledger.
"In March 2009 we signed the Stonewall Charter to show our commitment towards these issues. The RFL is the only national governing body to have joined the Stonewall diversity programme which raises awareness over diversity issues.
"All RFL staff undertake a mandatory equality and diversity training programme," he added.