Distrust of officials needs less evidence than trust does. [causal]
Ordinarily, I am likely to distrust you if I believe your interests strongly conflict with mine. (My distrust might make no difference for any action of mine, however, because I might have no interaction with you.) Often, this is the position we are in with respect to government officials. We can imagine that their interests are not clearly ours. Trust and distrust of government and its agents may therefore be asymmetric. We may have knowledge and theory to distrust when it would be hard to have knowledge or theory to trust. From a Humean or Madisonian view of the corrupting influence of having power with the discretion to use it, one can theoretically distrust government officials in principle as sometimes likely to use their offices for personal benefit in ways that conflict with the public interest or any citizen's individual interest. It is not so sensible to argue for a converse general principle that such officials are likely to share my interests and therefore to serve them.
Russell Hardin, Trust and Trustworthiness, loc. 749