While it is perfectly possible that an individual ideas or set thereof is entirely evil (I will not go into that because as I said I am not going where people would predict I would with it) it is a mistake to consider sincerity a mollifier for said evil ideas. People can very sincerely and earnestly believe falsehoods and lies. That does not make untruth truth, it simply means that the particular untruth is something that person X is quite prone to believe/accept. Just as Intent is not magical, so is sincerity in a belief not a panacea that makes a belief inherently valid in and of itself *because* said belief is sincerely held.
I could sincerely believe that if I lit a flashlight between two buildings that I could walk across the beam. In the real world if I tried the moment both feet are above the roof I'd fall down. The thing that bothers me about Evolutionary Psychology and other such explanations for how the individual beliefs of the observer are always the ones everyone else holds is that the real world does not work that way. It is to be expected people will disagree with each other civilly and that somehow, the harsh arbitrary cold and mechanistic Universe is not buggered beyond all recognition by that reality. While this is easily-stated I will be the first to state that it can be hard to remember and to act upon appropriately.
However at some level, there has to come a point where people can and will accept that sincere disagreement exists, and that if someone else interprets a statement or a political development differently than you or I do, that is simply the way that person sees it, not good or bad, it is what it is. There are enough real problems in the world that exist that creating fantastic conspiracies or assuming that people who hold extreme beliefs *must* be trolling as opposed to truly believing it (probably from the POV that sincerity = goodness as noted) simply makes life more complicated than it has to be. This is why it's a very bad idea to hold that modern beliefs/values must have evolutionary roots right at the start of the 150,000 years of human history. The beliefs are what they are, good or evil. Neither US progressivism nor conservatism have evolutionary roots in the age of machairodontines and woolly mammoths and we'd all be better off not to pretend that they do.
One more thing-it would also help if people remembered evolution is a random process based on sexual reproduction/selection, as opposed one guided directly to a specific means/end. We tend to see those only in hindsight WRT evolution as much as we do WRT everyday life. Species and cultures do not have predetermined ends or paths, all of it is rather more subject to individual development in some ways than we like to admit, much less so than in others. The real world is too complicated to fit into our personal boxes/grievances, and attempts to blame Ardipithecus ramidis for people we disagree with politically ignores that in the real world nothing ever develops as cleanly or consistently as we claim it does.
Conservatism and Progressivism both have precursors, both will have successors, and people who believe both do so with perfect sincerity on both. It's not a good idea for the two largest sides of the spectrum to have one side seeing the other as satanic and bent on destroying traditional values and the other seeing the other side as somehow transported across continents and decades wholesale.