The point isn't whether you gave only $200 to a political candidate, but that you are supposed to be impartial in your quest for justice, and these donations imply that you cannot be.
It's really simple.
A businessman giving to both sides to support his ventures in business and a senior DOJ official giving to one side, and then investigating the other doesn't amount to the same thing. At all. On any planet.
Good so if you get a ticket from a cop you should object on the grounds he is a registered democrat.
Republican police only for Tsing Tao?