I don't remember ever reading about Armenian genocide denial, or Native American genocide denial, or etc. The first times I ever found the phrase was in that.

I'm sure it was, but your personal experiences of the English language can hardly be used to draw conclusions about general usage. The rather general 'genocide denial' is a crime in Europe. 'Armenian genocide denial', whether you've encountered it or not, is regularly used (just google it) and is the title of a (long) Wikipedia page on the subject. Japan's position on the Nanking Massacre is regularly described as 'Nanking Massacre denial'. Similarly with the Rwandan and Cambodian genocides.

It is simply a fact that 'genocide denial' is the phrase in common usage for the pseudo-revisionist efforts -- which have accompanied every genocide I'm aware of -- to downplay their severity. There is no implied suggestion that these genocides were of comparable magnitude to the Holocaust.

Off the top of my head, 'X denial' is also used for HIV/AIDs, climate change, 9/11, evolution, vaccines, and the tobacco-cancer link. The OED defines denialist as

A person who refuses to admit the truth of a concept or proposition that is supported by the majority of scientific or historical evidence.

There is no additional requirement that this 'concept or proposition' is as horrific as the Holocaust. So I completely dispute that 'denial' is an 'emotionally loaded term'. It's a simple word with a straightforward meaning.

Quite aside from all this, your assertions about Dresden are completely wrong. The British view it as a horrific and immoral act, along with Lindemann's area bombing more generally. Justice is not achieved by burning cities to the ground.

On a final note, I agree the Israel-Nazi comparison is totally unreasonable. But the fact that some unreasonable people make such a comparison shouldn't cause you to thrust it by assumption on those of us who don't.