Smith had backed the global campaign against racism at the Solidarity Cup match in Centurion on July 12.
Smith was seen taking a knee while wearing an armband with the BLM logo on it along with 24 players, match officials, administrators and commentators at the ground.
Four former white South African players had expressed their displeasure with the support of the BLM movement. On the other hand, many black Proteas cricketers have taken strength from the global campaign against racism and come out revealing their stories of discrimination, prejudice faced over the years.
Smith, who is now Cricket South Africa's director of cricket, said there is genuine disappointment within the country over how the society is still fighting a battle for equality, almost three decades since the end of the apartheid era at the government level.
"It has shocked me how heated things have got. I get that in South Africa we've got so many issues and in some ways it is felt like we are bearing the brunt for government not having delivered on a number of things over the years and the frustration of that," Smith was quoted as saying by ESPNCricinfo.
"You pick up the paper or you click online and you all see all the negativity and the disappointment and the frustration in people's lives and livelihoods being affected, so it's been a tough period post that [3TC] game."
England and West Indies players were the first to show their support to the movement which triggered out of the murder of an Afro-American, George Floyd, in custody by a white policeman in the UAE.
Leading up to the Solidarity Cup, when asked for his thoughts on the two teams' act at the start of the Test match in Southampton, South African pacer Lungi Ngidi said he would definitely like his fellow countrymen to also take their stance against racism.
This, however, erupted a storm, as a day later, Pat Symcox, Boeta Dippenaar, Rudi Steyn and Brian McMillan criticised Ngidi and questioned whether he has similar connect with the victims of farm murders.
Smith, who supported Ngidi even back then, through social media and at the game at the SuperSport Park, once again backed the young quick.
"Lungi, in my mind, said nothing wrong. He expressed an opinion - he didn't make a statement - and expressed the fact that the team was going to get together and have a conversation and in no right did he deserve to be attacked. What happened to him and the way the guys came at him is entirely wrong."
South African players have since been vocal about the campaign aimed at eradication of the deep-rooted social malaise in racism and will also be taking part in a culture camp at the Kruger National Park this week to discuss team identity and values.
"Within the space, we've handled it extremely maturely. We got together, we listened, the conversation was open, people shared and we decided to support each other in this movement," said Smith, pleased with the unity on this matter.
"That's what taking a knee meant to us. The fact that we are all together. I haven't seen the team having such an honest conversation in a few years, which is great."