The answer hints at political preferences. A voter who retains the citizenship of the aggressor state is biased from the start. They either vote for those who promise as many advantages as possible to people in their situation – whether these are the Social Democrats or the Center Party – or they support persons and organizations that are more compatible with their world views. A good example of this is the political party Koos along with the infamous Aivo Peterson. In other words, with its decision, SDE is seeking votes either for itself or for people and political parties that hate Estonia.
This is an exemplary disservice to Estonia, but a great friendly favor for Russia. Usually, resources and money have to be spent to establish a loyal person in a position, here they are voted into local governments completely free of charge thanks to Estonia's new coalition. The situation is made especially amusing by the fact that the Riigikogu declared Russia a terrorist state supporting terrorism in 2022. In other words, the position of the Social Democrats now is: «Let the terrorists vote!»
The Reform Party has exhibited the ability to be strong in foreign policy: to protect Estonia’s interests, to stand up against Russia, to support Ukraine. However, in domestic politics, it now showed weakness instead. Stripping Russian citizens of voting rights remains the best possible decision, the implementation of which has not been carried out despite promises. The decision to abandon it will have negative consequences for all parties involved and for Estonian society in general. As a Russian citizen, I continue to believe that persons with my citizenship must not be able to vote in Estonian elections.