Has anyone making jokes about murdering vegetables seen Seth Rogen's movie, Sausage Fest? Your jokes remind me of the movie and I'm cracking up.

Every living thing consumes. Something must die for us to survive. Everything that dies goes back to the earth.

To kill for sport, power or wealth, in my opinion that is what is unethical.

it is if you eat them or are protecting livestock

Yes, yes, and it depends (but only in that order).

All creatures must die, and of all the agents of death, humans are perhaps the only ones who have any concern, to lessen or minimize the suffering that dying brings with it. The symptoms of old age, disease, starvation, parasites, natural predators, and cancer etc., none of those care how much suffering they cause during the process of death. So that in many ways you could say that those who are killed by human hunters or slaughter-men, are the lucky ones, and that in all probability our killing reduces the overall amount of misery in the world.

What is much more questionable, is the farming of livestock. It seems very doubtful that taking animals from their natural environments, and locking them in tiny cages, where they rub themselves sore on the bars, and spend most of their lives lying on their own waste, without contact with sunlight or normal social interactions with other members of their species, often prone to disease through mismanagement, and drugged to make them passive and faster growing, and bred with painfully distorted bodies, to enlarge the parts we like to eat, giving birth to unnaturally large offspring and litters and frequently intensionally terrified to make them obedient, really does not increase the net amount of misery and suffering in the world.

You could make a good case not for veganism, but certainly for wild game and roadkill only.

Death is a part of life. You kill for necessity as a part of life. You will die as a part of life.

When killing becomes fun or a selfish pastime, that's a problem. The olde "waste not want not" principle sort of applies. If you are going to kill, try to utilise all parts of the animal or fish. I think this is why people get so disgusted when elephants or Rhino's are killed purely for their ivory, or sharks for their fins, with the rest left to rot.

No. I must confess I do kill a zucchini now & then

I don’t know about ethical, but yummy.

Depends on whether we choose to take the animal’s perspective into consideration, but until we get the ethics ironed out, I feel it’s an unpleasant adult responsibility that we need to accept, with the least attendant guilt as possible. I always liked stories I heard about indigenous practices that involved ritually thanking the animal for its life, before consuming it. Just a simple mindfulness of how one’s behavior affects other creatures’ lives.

It’s not ethical to kill wastefully.

To be honest, I don't really know is there's an answer to that or even how to determine what it is if there is. That is why I only concern myself with being logically consistent on that point. If you play both sides, and there is an answer, you're definitely wrong somewhere, but if you're consistent, you still have the possibility of being right.

Two small side notes:

1. 'Fitness' of organisms has, for billions of years on Earth, been directly related to how well they could destroy other life forms, consume them, and use those resources to make more copies of themselves.
2. It is likely impossible for a human to exist on this planet without killing other animals either directly or indirectly.

Ya gotta eat.

Yes.