There are, in fact, plenty of other countries that do this. Many countries, including Israel, Greece, Ireland, Armenia, have simplified immigration procedures or grant automatic citizenship to people with ancestry tracing to those countries or related ethnicities. Spain also grants expedited citizenship to Sephardi Jews.
There is variance as to whether these countries grant automatic or expedited citizenship, and whether qualification is based on ethnicity or nationality of ancestry, but you can look through the Wikipedia article to find that a number of countries have laws of return.
Mind you, that doesn't establish a legal precedent for white South Africans hoping to emigrate to Europe, and indeed your article doesn't say that it does; it says that those wishing to emigrate are making a moral (rather than legal) argument.
Furthermore, laws of return should be distinguished from the legal right of return established by the Universal Declaration of Human Rights, which only protects the ability of individuals to choose to leave their countries without fearing they cannot return. It does not apply on the basis of ancestry or ethnicity.