More dumb questions
The animal-rights people make an interesting point, even if it's one I don't necessarily agree with. For me, though, it raises more questions than answers.
What would happen if we found out that the plants knew what was happening to them? Or suppose we found out that consciousness isn't strictly necessary for suffering. And even if we can dismiss those questions easily, there may be other forms of life in the omniverse, and how do you wrap your human-centric ethical world view around them?
I guess my biggest objection to animal rights is the tidy coincidence that we're in favor of them because we are animals. And don't you find that people show more empathy towards animals that are the most like us? You'll get a lot of agreement by saying we should be nice to the kitties, or puppies, or pretty much pick your mammal. If you try to tell people not to be mean to the fish, or the snakes, or the worms, or the beetles, or whatever, you're going to lose a few converts to the cause. Hey, it's not the worm's fault he's a worm.
When we finally find life on another planet, it probably won't be any easier to communicate with than an earthworm, no matter how intelligent it is. And at that point, it'll be much easier to just pretend they're primitive and massacre 'em. Of course, they might feel the same way about us.