I will give you an example. If I am a Chinese journalist, and I hear of a story that Chinese people in Tibet have been attacked or killed. Surely this seems as if some innocent people have been attacked unjustly. I would report this as such in state media, saying that "insurgent" and "extremist" Tibetans attacked local residents.
On the other side of the coin, these Chinese people, while not having killed or attacked any Tibetan people are contributing to cultural genocide of these Tibetan people. 70% of Lhasa, the largest Tibetan plateau city, is now Chinese. Tibetan people only own about 10% of the businesses in the area, large and small. Reports in the 90's of the state government funding copper mining in the area, and subsidising Chinese people that moved into the area have been claimed, however I cannot recall if they are confirmed.
A person writing from the side of the Chinese media can say local people were attacked. This is true. However, this ignores the reasons why the Tibetans attacked them. Chinese people in the area are an economic class above those local people. They run the local government in Chinese language, and their culture thrives as ancient complexes such as Larung Gar (thediplomat.com/2017/08/china-tears-down..
are destroyed due to laws created by Chinese government officials.
Now, this situation can be seen as a problem if you believe that the Tibetan people have a right to their autonomy. Accepting this means you may agree that cultural diversity is beneficial to society, that the Tibetans have a right to the products of the land (In Tibet's case, copper which was mined by China.) If you want to know more of a people's collective rights, see Third Generation Human Rights. Other rights by this are language and cultural preservation, self determination, self government, and restitution for lands taken from a collective people.
Now for the comparison to South Africa's situation. Firstly, South African Boers are in a different situation to ethnically Chinese Tibetans, being a vast minority, whereas if Tibetans were to attempt this policy, they would simply be suppressed by the majority Chinese population. Similar situation with Palestinian people and Israel. In all these cases, the group with traditional ownership of the land, according to human rights law, has the collective rights stated above.
Following on from the Human Rights perspective, the South African peoples are having their rights infringed upon, due to not having land rights, and until recently governmental rights and language and cultural heritage. So In this case, As a group being suppressed, the logical thing to do is stop the people with the economic power. While Palestinians, Tibetans and black South Africans are in differing states of numerical majority/ minority, If reasonably accounting for the opposite groups, they are all in a social and economic minority, while being in a majority population. While they may be reasonably be able to force the boers off their land without violence, the perspective of those people, as a suppressed group, means that individuals may believe that it isn't feasible for such a lengthy process to happen, when they risk economic insecurity under a group which has the ability to control much of the job market.
In a point based not on the issue, but on Lauren Southern as an individual, it is wrong to rely on what this youtube video attempts to be, Journalism, as objective and factual when considering a Journalist's job. Southern, as someone who has fired flares at migrants in the Mediterranean sea while yelling racist slogans, cannot be considered a source of objective reporting when considering activism's philosophical conflict with journalism. Journalistic professionalism relies on fairness, factuality, disinterestedness and nonpartisanship. Whatever your belief on migration of multiple groups to the EU, Southern's clear display of activism, specifically activism "risking loss of life", according to Patreon when deactivating her fundraising activities, cannot be a reliable source of information, due to her unfounded biases. Biases in journalism are unacceptable. For instance, many corporate networks across the world have a Neutrality bias. People may see other networks as politically biased. Journalism should rely on objectivity. Lauren Southern, by record of her past activities, cannot engage in reliable Journalistic work such as reporting, regardless of your agreement of disagreement.