I think right and wrong is *VERY* subjective. There are no universal laws on what's right/wrong and good/evil. Many things based on our sets of morality can be interpretted to us as one way or the other, and some seem so ingrained as "bad things" to us that they seem to be just naturally wrong.
As an example, to us, killing an ant (or even an ant colony) is the "right" thing to do if they are intruding on our living quality, as we consider them an inferior life form. What if one day in the future, we develop space travel, etc., and there's an alien race who deems us inferior and we are intruding on their life/comfort? Do they have every right to destroy us?
Some people may argue that killing an ant is wrong. Ok, that's their choice on the issue of right and wrong. There are also ants that can kill people, if threatened by one of these, or even approached with the possibility of being bitten/stung/whatever, is the human within his rights to kill it? What about in our above scenario with some alien species? What if they feel that our presence is a threat to even one life of their race? Would they be within right to kill said humans?
Once again, the answer as to if it's right or wrong are subjective. I'm sure the human has a different view of what is right and wrong in these two situations than either of the opposing parties (aliens or ants). The ants don't generally have a concept of right and wrong as far as we can tell, all they know is there is a human which can kill it, or it (or they) can strike first and kill. The aliens obviously think protecting themselves is the right thing, which is the same the humans most likely think.
now, obviously, this is an abstract scenario, but it helps convey my point.