So if suffering isn't ethically inacceptable, then torture of human beings is also OK for you? To me it seems that what you're saying essentially means that you just don't have any morality at all.
This 'herd instinct', by evolutionary necessity, will tend towards in-group altruism in any social animal, but the details, the bylaws, and everything else will be driven by accidents of history and by fashion. It may be that one day that the great human herd of western civilization will collectively decide that eating meat is evil; I sure hope not, I prefer our current fashions (but then I would, having grown up with them.)
In fact, I actually think that would be a very dangerous attitude to take, since I would believe that the only person who would be suffering by my taking any means necessary to change the world however I like it would be me, who would of course be perfectly willing to do so.
Even if morality was just herd instinct, what you were saying previously is that suffering for you is not immoral. And even though, many intelligent people saw absolutely nothing wrong with torture, what about you, right now?
What I'm getting at is that your original statement which basically said "suffering is OK" (you didn't indicate any restrictions or conditions) is just bullshit.
When someone says that something is not immoral (or evil), they can be arguing to things: either it is moral, or it is amoral (i.e. is not affected by qualifications of morality). The GP is arguing the latter: that, in the context of nature, suffering is an unavoidable consequence of competition for life. Is the lion evil for targeting the weakest wildebeest? Is toxoplasmosis evil for disrupting the fight-or-flight response of its host?
Now it seems the next argument that will come is that we as human beings are also animals and part of nature, and therefore we can also kill other animals as e.g. lions do.
Well, a female mantis occasionally decapitates its male mates after copulation. Does that mean that it is moral for women to do the same to men? Amezarak's original statement is just too broad.
No one is arguing that nature is moral.