writing an essay on interspecies ethics would be pointless.
If I may translate this and add capital letters which you seem to dislike so immensly: "I am incapable of either thinking about the issue of interspecies ethics or expressing my thoughts about it via written language.
Let me explain it to the anti-PD crowd again really slow.
We don't need something like the PD on Earth because we are one species with one set of ethic principles. The difference among cultures are negilible.
We do need the PD in space because Klingon ethics differ from Ferengi ethics which differ from human ethics. Suppose you meet a bunch of Klingons for the first time and they brawl with each other. Your human reaction would be to interfere and seperate the fighters, this is after all what you would do in the case of any bar fight. Yet these very Klingons do not appreciate the interference, they do actually enjoy the fight.
Suppose they wanna execute one of their people. This is totally wrong from a human / UFP point of view but if we interfered all hell would break loose.
About the black-and-white stuff, this means that Starfleet captains can do whatever the hell they want. If you are in the right mood you help, if you aren't you don't. In other words, you evade the ethical issue via charity. I kinda prefer something less arbitrary.
What the anti-PD crowed advocates is that humankind should conquer the galaxy during the day and rcompensate for this in the evening via doing some charity. This is utterly wicked and gladly it has nothing to do with Trek at all.