To some extent complaints are treated as testimony to the success of democracy. We can prove the statement by analysing certain facts like :
(i) Slow and inefficient government: Some people complain that democracy is a less effective government and it is slow in functioning. There is no doubt that non-democratic governments can be more effective because they are fast in their decision making. But it is not certain that decisions are right or wrong.
(ii) Unsuccessful in reducing economic exploitation: There is no denying the fact that democracies do not appear to have been successful in reducing economic inequality. But, it is only possible in a democracy that people can raise their voice against not only economic inequalities, but also against all types of inequalities.
All these facts show that complaints are treated as testimony to the success of democracy.