It's cynical of the ANC to say that Dianne Kohler Barnard's fall is "a convenient publicity stunt". The ruling party criticised the DA following its expulsion of the politician on Friday. The ANC also said that the decision would do little to cleanse the party of its "twin demons of racism and apartheid rule".But how else is the DA supposed to tidy up its reputation if it does not take firm action against party members who show signs of racism? Kohler Barnard was found guilty of misconduct for sharing a Facebook post praising apartheid-era president PW Botha, for which she has apologised "unreservedly".When the scandal broke, at the beginning of last month, the DA demoted Kohler Barnard, who was its spokesman on the police, to the back benches of parliament and relegated her to being deputy public works spokesman.But following a meeting of the party's federal executive on Friday night, her membership of the DA was terminated.A DA MP, who asked not to be named, told Afrikaans Sunday newspaper Rapport that many people were shocked at the decision to withdraw her membership."They want to make an example of her. This is a political execution."A sympathiser told the newspaper that the punishment did not fit the crime and asked what precedent was being created by firing Kohler Barnard.Is it perhaps not the best possible precedent?Is it not exactly thoughtless actions such as Kohler Barnard's Facebook post that perpetuate the party's reputation for having "twin demons of racism and apartheid rule".By acting decisively and expelling Kohler Barnard, the DA is making a clear statement to its members that it will not tolerate racism and that it is taking its transformation seriously.The ANC should follow suit and rid itself of corrupt members.Taking action against politicians who do not follow the ethos of our constitution should be encouraged...