Agreed. Theory of evolution is a descriptive theory. Anything is selection of the fittest as long the traits survive. Otherwise it's called discrimination. Theory of evolution has nothing to do with decisions we make because it always applies, no matter what. One could be against adoption because "it's against selection of the fittest". But we evolved to be (some say) a society conscious animal.
Another example. One can be against transgenic food because it reduces biodiversity. But indestructible rice has clearly some evolutionary advantages. Until the day (in 1 century, say) a bug appears and we have no more rice.
Anyway, like you say, our reasoning about all this stuff is part of the evolutionary process. The only thing I think we should be aware is than on this kind of stuff, the precautionary principle is more applicable than our usual "innocent until proven guilty principle". The precautionary principle says "If something you're doing can have a irreversible impact, it should be proven safe first". We already apply this to pharmaceuticals, and many other things but we should be more aware of it, because in a way, is counter intuitive for us, democratic people.
Who cares if it's debatable if there is global warming? Just because that there is the risk of it, we must take action to prevent its possibility. This ruins 99.9% of the arguments of GW deniers and conspiracy theorists. Because they think GW should be proven, whereas the only thing to be proven is the mere possibility of it.