It is reasonable. Many totalitarian governments hide crime statistics. Many badly run police forces discourage reporting certain types of crime, like theft or robbery, to not mess up their stats. Of course, at some crime level, the difference between the official picture and the reality becomes impossible to hide, but the pretense usually lasts much longer even if it's obvious how hollow it is. But yes, it is very rational for the government whose interests are detached from the interests of the citizens, to manipulate the data, and they frequently do.