You're right that science should be objective. You then say that evolution is an observable phenomena. Well then, how could a paper disputing evolution be objective?
They're welcome to submit such a paper, as long as it's good science. It's not threatening, it's just potentially misleading to people who read it and gives the author the chance to claim legitimacy through publication. That's what the peer review process exists for, to weed out bad science, so that the general public is not required to try to evaluate claims that require expertise they don't have. Again, it certainly has its problems, but it's better than outsourcing to non-experts. Peer review can also sometimes be politically motivated, but, at least in my experience, that's often the argument of someone who's angry because their paper was rejected for legitimate reasons.
The fact that you think "AGW" is simply and provably false is also a beautiful demonstration of why we need peer review. You have a ridiculously simplistic view of the issue and of the status of consensus because you're opining on a question that's outside your field. (I'm just guessing, but you're not a climatologist, are you?) There are a lot of "experts" like yourself making similar claims who have no idea what state the field is in. If you tried to get such a paper published, professional climatologists would say, "hey, we're not idiots, we study this for a living and have taken basic physics and chemistry. Nice try." And they would send your paper back, as they should.