Wallace and veteran striker Kenny Miller, neither of whom played at Hampden, have both been suspended and ordered to stay away from the training ground and the stadium pending an investigation into their alleged misconduct.
However, McCulloch believes that it was Wallace’s duty to speak out following the gutless display at the national stadium.
“Having been at the club for as long as he has and having the role of club captain, Lee should have a say. Whether he’s in the team, on the bench or up in the stand, it’s his responsibility to speak to the players and for them to speak to him,” said McCulloch.
“But it’s not like the old days any longer – you can’t shout at the young players now because it’s deemed as bullying so football has changed. But, again, I don’t know exactly what was said on Sunday.
“I’ve deliberately not spoken to him but I know he’ll be hurting like everybody else would be. His Rangers career could be over; the club have deemed it to be something they are not happy with and they’ve acted.
“I can’t really comment on that situation because I don’t know what he said or how he said it. I can only comment on what Lee Wallace is like as a guy [and] the captain is a link between the dressing room and the manager or the management team.
“There is a way to conduct yourself, though – there’s a way to be a Ranger, which I learned from Sandy Jardine. It would be a pity if this is the end of Lee’s Rangers career. He’ll be gutted at that, I’d imagine.”
McCulloch was at pains to stress that this issue should not cloud Wallace’s commitment to the Ibrox club.
That was underlined for him when he effectively sacrificed his international career by staying on following Rangers’ financial meltdown six years ago.
“Lee Wallace is the club captain and all I can say about him is that, when the club was in turmoil in 2012, he was my vice-captain and we both decided to stay,” he said.
“He was loyal to me and he wasn’t disruptive – he would ask my opinion on things and vice-versa.
“He remained at Ibrox and I think he’s shown his loyalty to the club over a period of time. I don’t know exactly what happened after Sunday’s game but, in modern-day football, there is a line you can’t cross.
“However, I’m only going on the Lee Wallace that I know and was in the trenches with and played in big games alongside.
“In every dressing room I’ve been in since I came through at Motherwell at the age of 16, there have been arguments and there have been fights but maybe that was just part and parcel of the old-school environment.
“But when you have an Old Firm game and the pressure that brings, plus the chance to reach a cup final and you lose in that way, I think I – as a captain – would have had something to say to everyone afterwards.
“It’s not been the best of weeks for the club and everybody associated with it but the biggest thing for me is the manner of that defeat against your biggest rivals. That’s the real disappointment for the fans.
“Everyone has lost Old Firm games but on Sunday there wasn’t much fight or passion from Rangers – there was nobody playing for the shirt. It didn’t seem that the effort they put into other games was matched.”
McCulloch claims it will take Rangers several years before they are in a position to challenge Celtic, never mind overtake them.
They have not made the hoped-for progress under the current board and continue to lose money, while the fans continue to have very high expectations.
McCulloch argues that it would have been more helpful if the Ibrox board had pleaded for patience and fully explained their financial position rather than chairman Dave King issuing a statement prior to the Celtic tie demanding “instant success” from the next manager.
“It probably would have been better,” he said. “It takes time. It will take money and a change of mentality. Being realistic would help, definitely. The fans want to know what is happening and they are rightly getting frustrated.”
l Lee McCulloch was speaking to promote the Scottish Grand National at Ayr Racecourse on Saturday.