There can be "no ifs or buts" when it comes to racism, said Leader of the Opposition Pritam Singh, stressing that those who hold such views should reflect deeply on how these can hurt themselves and those around them.
"Bigoted views, even if privately held, have a nasty habit of showing themselves up opportunistically in day-to-day circumstances," Mr Singh added in a lengthy Facebook post last night.
The Workers' Party (WP) chief made these comments in the wake of a Facebook video showing ice cream store owner Dave Parkash, 26, and his girlfriend Jacqueline Ho, 27, a user experience designer, being harassed by Ngee Ann Polytechnic lecturer Tan Boon Lee in Orchard Road on Saturday night.
Mr Tan, 60, who has since been suspended and is assisting police with investigations, had berated Mr Parkash, who is of Indian and Filipino parentage, and told him it was a disgrace for a Chinese girl and an Indian man to be dating.
He accused Mr Parkash of "preying on a Chinese girl", adding that the "Chinese don't like it", and also told off Ms Ho, who is part-Thai and part-Singaporean Chinese.
Ms Ho filmed the exchange and Mr Parkash uploaded it online. He said he wanted to raise awareness that racism still exists here.
In his post, Mr Singh affirmed that everyone is entitled to his or her private views. But as a multiracial and increasingly multicultural secular society, the public space is a shared space for all Singaporeans to participate actively in - regardless of their race, religion, sexual orientation and so on, he added.
"Should we not as a society call out bigoted private views with a view to make the public space safer and accommodative for all?" he said, adding that the lecturer had made the "serious and fatal misjudgment" of taking his views out of the private realm and into the public one.
Calling out such views would be a learning opportunity to self-reflect, unpack preconceived notions, and determine what sort of society Singapore aspires towards, Mr Singh said. He noted that the "determined yet restrained" response to Mr Tan's diatribe from all segments of society - including politicians as well as the general public - represents a silver lining.
This swift backlash shows that such views are not acceptable in Singapore today, Mr Singh said.
Law and Home Affairs Minister K. Shanmugam, Education Minister Chan Chun Sing and Culture, Community and Youth Minister Edwin Tong had earlier spoken out to condemn Mr Tan's actions, as did WP MP Leon Perera.
In his post, Mr Singh also made reference to comments by founding prime minister Lee Kuan Yew in his book Hard Truths, noting that Mr Lee had seemingly held both private and public views about interracial marriages.
In the book, Mr Lee had spoken of how interracial marriages had helped some racial communities better integrate into Singapore society.
But he had also expressed reservations about such marriages, asking interviewers: "Supposing an African black were to marry your daughter, what is your reaction? You will cheer or you will tell your daughter, look, think again, right? I have no qualms in telling you that I'll tell her 'you're mad'."
Opposition to interracial unions among people of Mr Lee's generation is not uncommon across the various races, Mr Singh wrote.
"Their views tend to evolve towards greater acceptance when they see the happiness in their children's eyes over the choices made, or when the grandchildren come along. Even so, most, if not all, keep these views private and do not gratuitously share them in public."
Mr Singh said "tectonic shifts" in societal norms are taking place, especially between older and younger generations of Singaporeans, adding that he and his WP colleagues appeal for greater understanding and mutual respect, even as they work to promote efforts to eradicate bigotry and racism here.
"The secular public space belongs to us all, not one single racial or religious group or community," he added. "And there, we practise tolerance, give-and-take and make adjustments so that everyone is a proud member of the Singapore family."