Heritier Lumumba has criticised Collingwood and president Eddie McGuire for their response to a damning report into systemic racism at the AFL club.
An independent investigation - commissioned by the club's board last year in the wake of allegations from Lumumba - found Collingwood guilty of "systemic racism" and recommended significant changes to its culture.
After details of the report emerged on Monday morning, McGuire, chief executive Mark Anderson and integrity committee members Peter Murphy and Jodie Sizer fronted the media that afternoon.
But in a lengthy press conference, McGuire described the occasion as a "day of pride" and insisted there was no "shame or disappointment" - despite the report's damning findings.
On Monday night, Lumumba said Collingwood's press conference was a "bizarre response to their own report finding them guilty of systemic racism" and was particularly critical of McGuire's attitude towards its findings.
"It was painful to watch the club dig itself deeper into delusion and dishonesty at today's press conference," Lumumba said on Twitter.
"Eddie McGuire's inability to let go of the illusion he's constructed of himself does not serve the Club, the code, or the community.
"It's a pity his final year looks like it will be marked by yet another self-inflicted racism scandal.
"The report clearly states that during Eddie's tenure as CFC president, the club's racism resulted in "profound and enduring harm" to many individuals, families, & communities.
"It was disturbing to see how easily Eddie and the CFC board members reduced the severity of this 'profound and enduring harm' to mere 'mishaps' - as if they were talking about spilling tea on a couch rather than being found guilty of years of systemic racism."
The report found racism at Collingwood had resulted in "profound and enduring harm" to First Nations and African players and the club's response had been "at best ineffective or at worst exacerbated the impact of the racist incidents".
Some of the racist incidents highlighted in the report involved McGuire or occurred under his watch as Collingwood president.
Lumumba, who has previously alleged he was nicknamed "chimp" and that a culture of racist behaviour existed during his time at Collingwood, chose not to participate in the investigation.
The report's authors said it was not appropriate to review Lumumba's allegations without his involvement but stressed the need for a serious investigation into the former Magpie's claims, with his participation.
Lumumba said he intended to speak to the media on Tuesday.
In October 2020, he lodged a claim in the Supreme Court against Collingwood and the AFL over racist abuse he was allegedly subjected to during his playing days.
