Politics (n.) the activities associated with the governance of a country or other area, especially the debate or conflict among individuals or parties having or hoping to achieve power.
If someone tells you not to politicise anything the government or its opposition does, that person is an enemy of democracy. Anything to do with the national revenue and how it is spent is a political matter and politicising it is the right thing to do if only to inform the people of the motivations for a particular government policy.
For example, the Commander-in-Chief, in response to the situation in Laikipia, has ordered the deployment of the Kenya Defence Forces to the area in order to "stop the banditry." The President's supporters will argue that the security situation has deteriorated to such a state that ordinary and extraordinary policing tactics are insufficient and that only the army can restore peace and order. The President's opponents will argue that the timing of the deployment is suspicious because many of the alleged victims of banditry have not been offered any help; only those victims of British origin have.
Both may be right and it is to politics that the rightness or justness of a position will receive the implicit or explicit imprimatur of those being governed.
In Kenya our problem has never been the politicisation of issues but that those doing the politicising are frequently bad politicians. Their politicisation of issues are frequently not about ultimately achieving power but "destroying" their "enemies". Few of them have the true politicians' ambition of achieving presidential power; many of them are interested in the rent-seeking opportunities their political positions afford them especially when it comes to the tenders that the government floats for major works.
For this reason, much of the politicisation of issues that takes place is designed to paint individuals and ethnic communities in stereotypical colours: this community is full of thieves, that community is full of watchmen and cooks, that other community is full of terrorists, the other community if made up of bandits, and so on and so forth. In this way, there is no need to discuss issues of power-allocation or resource expenditure. It is then possible to hide ones true intent: a piece of the tender that the government is floating.
The victims of these machinations don't see themselves as double victims of the corruption that is engendered or the stereotyping they are subjected to. If "their man" prevails over one of "those people", they are persuaded that their community has won. If their man loses, so too does their community. And thus, whenever their man declares that a matter should be "politicised", they offer him their full-throated support.