Why do federal district courts not try cases dealing with military matters, grievances against the government, or tax disputes?

Congress has created specialized courts to deal with such cases.

Explanation:

Federal courts handle civil rights cases. Because military cases, government complaints, and tax disputes often involve matters beyond civil law, federal courts are not the most appropriate to handle such cases, so the government has determined that other courts deal with such cases, so that cases could be resolved as best as possible.

i see, would you mind putting it as one?