The five-time Super League champions sported red and pink haircuts at St Helens, having agreed to do so in aid of Sport Relief if a certain amount of money was raised prior to kick-off. However, they were left red-faced on the pitch, though, with a resurgent Saints side running in eight tries in a 46-6 win.
That led to Leeds being branded as "unprofessional" during a television commentary and Peacock said on his Twitter account: ""To anyone who thinks we lost because we had red or pink hair; you are clueless."
He added on the club's website: "Our hair colour had nothing to do with this game and anyone who says that obviously doesn't know how this team works.
"We are trying to raise awareness and funds for a great cause.
"At the end of the day, this was a disappointing loss but we will come back ready to go again next Friday.
"There are people who have horrendous lives around the world and by having a small bit of embarrassment personally, we can raise funds that might save someone's life.
"If I was asked to do it again, for that reason I would do, 100%."
Coach Brian McDermott told former Great Britain hooker Mike Stephenson that he was "bang out of order" for the commentary.