Debunking Holocaust Denial - Denier Argument #3: All extermination camps found by the Soviets?

In this post, a denier tries to claim that the extermination camps are a hoax since they were all found by the Soviets.

Yet again, deniers are continuing their usual habit of misrepresenting Holocaust history and failing to do basic research on the Holocaust. By doing this, they show the world how stupid they really are.

First off, there is no evidence that the documentation and evidence of the extermination camps had anything to do with the liberators of said camp. Even before the camps were liberated, there was already (albeit limited) documentation of the camps. Take, for example, an aerial photo of Auschwitz-Birkenau from 25 August 1944 (Before the camp was liberated):

Documentation of the extermination camps before their liberation essentially makes the possibility of the Soviets building the extermination camps impossible, as the locations of these camps were in enemy territory yet photos of them existed.

Research and documentation on the Holocaust was not done solely by the Red Army and Soviet government as the denier suggests; rather, it comes from multiple other sources. The Nazis themselves documented their own genocide by taking photos and sending telegrams and other messages regarding the Holocaust. There are thousands upon thousands of testimonies regarding the Holocaust by its victims. Most notably, historians are responsible for lots of documentation and research about the Holocaust, including non-Russian and non-Soviet historians. 

I'm not sure why the denier believes that every single piece of documentation on the extermination camps was done by the Soviets. I guess deniers lied, again.

Secondly, the denier's claim that the Soviets specifically would have faked mass murder of Jews is false. The Soviet Union actively censored and left out the fact that majority or all victims were Jewish in their reports of the Holocaust. The book "Black Book of Soviet Jewry" was censored in the Soviet Union after it specifically focused on Jewish victims of the Holocaust. The Soviet report about Auschwitz did not mention Jewish victims. 

It is worthy to note that the Soviet Union was also somewhat anti-semitic. Beginning in late 1948, the Soviets launched a campaign known as the "anti-cosmopolitan campaign" in which they accused the Jews of being "rootless cosmopolitans" and persecuted them. 

Sources:

The Case for Auschwitz by Robert Jan van Pelt, 2002, Indiana University Press, p. 175

http://holocaustcontroversies.blogspot.com/2019/08/nazi-document-on-mass-extermination-of.html

http://holocaustcontroversies.blogspot.com/2015/10/contemporary-german-documents-on.html

https://www.ushmm.org/remember/holocaust-reflections-testimonies

https://en.wikipedia.org/wiki/The_Black_Book_of_Soviet_Jewry

http://holocaustcontroversies.blogspot.com/2017/05/rebutting-twitter-denial-most-popular.html#auschwitzplaque

https://en.wikipedia.org/wiki/Anti-cosmopolitan_campaign