I haven't done so. Simple. Everyone has a bias, in terms of pov, but the biases that you will see on denier sites etc are of a different sort: they are prejudice and outright hatred. There is much that is paranoid or delusional. It is necessary to call this out, actually. Why is anti-semitic in quotations marks in your post, by the way?
First, I posted that scholars weed out bad sources. They do more: they compare and critique them. So you are only making the same point I already made. Second, no, I am far from saying that the genocide consists only of gas chambers. Perhaps, whilst generalizing about my posts, you haven't actually read them. Just a bit upthread I summarized the ways in which extermination took place and, based on Hilberg, gave 2.5 million non-gassing deaths out of 5.1 million Jews murdered. I haven't, in fact, posted much about the gas chambers. Third, what does not "necessarily" denying the open air shootings mean? Why "necessarily"? Did they occur or not, in what magnitude, and how do you know? Why do they "make sense" but not other forms of killing? Based on what evidence?
As an aside, I myself think that the open air shootings make no sense, are improbable, and are extreme enough to cause a kind of cognitive dissonance along with moral repugnance. The way to understanding them, just the same, is reading the evidence for them, how people processed the actions, and discussions and analyses of them. However little (common) sense these extermination actions make, they happened. Ponar meant death, frankly.