Many vegans have thought deeply about the arguments against a diet composed of meat and other animal products. Some have not. For example, when asked, why not also limit the number of plants you kill and displace from their natural environment?, vegans often act defensively or attack.
I wanted to write a parody of the PETA website to illustrate the point that plants also require consideration. It was a weak satire. I found a much more complete essay here:
http://www.vegetus.org/essay/plants.htm.
I highly recommend you read it carefully if you are vegan.