Oh no, you aren't the only one who's noticed this. It always got me that for nature based religions, it always surprised me how people tend to ignore how harsh and brutal the natural world can be, but yet there is still a beauty to be found in it and if anything it inspires a different kind of respect for the power in the natural world, we tend to forget the power it holds now. But then I'm a Heathen and we tend not to be quite so fluffy, at least in my experience anyway. This band, while not pagans themselves, they use Norse mythology quite a lot in their lyrics, but more thoughtful and subtle than a lot of other bands, but this video reminded me of the great power in nature, even although waterfalls and rivers don't seem it, when you get battered around in one you will appreciate they do! [link] Sorry if you don't like the music but I've loved them for so many years and for good reason.
Black and white, evil and good. The way I see it, while I don't like evil, to me it is almost necessary. If there were no evil, then how would we define good? Would the act of doing good loose it's value and meaning, would only the highest of good become worthy and lesser good become the new evil? See where I am going? I'm not advocating it, but it helps bring perspective to things, or as I saw written, it is only in darkness that you see the stars.
As for deities that are considered to be bad, evil or negative, while some people will hate me for this opinion, in some ways there are some that reflect what humanity is like. Take Loki for example, he is often the mischief maker who either by design or by accident brings trouble upon himself and/or the other gods and goddesses and somehow makes things come right, but as you see in the death of Balder, Loki's capture and Ragnarok, you could say that it stemmed from his jealousy of Balder's gift from his mother to be harmed by nothing and then revenge against the gods for his imprisonment. Jealousy and the desire for revenge are all emotions we have felt or will feel, and in those myths you see how destructive they can be at their worst. While destruction is not always bad, and sometimes destruction is necessary to create the new, it's not hard to see that this does rather reflect one aspect of what we can be like.
Well I have to say I appreciate that the Norse deities are not these "perfect" figures. I know some will say that is just how they are but I can't help think that by this there is something to be learned about how we are ourselves, warts and all, ether from them or from the myths and what happens in each one.
The thing is it is a common thing to have such evil figures with such negative traits throughout many cultures. I sometimes wonder if by making caricatures out of these and presenting them as deities, monsters or whatever, that it was maybe a primitive way for humanity to hide the fact that in the end we have the potential to be the source of the greatest evils and all the evil that has happened in history has been caused by mankind against each other. We don't like to face up to that fact so we make baddies, monsters and boogie men, maybe as a way of dehumanizing the evil humans do to each other.