I'm going to read through the page this website links to that debunks the Leuchter Report specifically in more detail. Concerning the contents of your link itself, here is the article's conclusion:

Drawing moral equivalences are problematic as the existence of other horrible crimes do not negate the crimes of the Nazis. Holocaust revisionists are actually Holocaust deniers as they reject many of the core aspects of the mainstream historiography of the Holocaust. Like creationists abuse the internal scientific debate between phyletic gradualism and punctuated equilibrium as if it was a debate about the validity of common descent, Holocaust deniers abuse the internal historical debate between intentionalists and functionalists in an attempt to spread uncertainty and doubt regarding Holocaust history at large by quoting historians out of context.

The swimming pool at Auschwitz was a water reservoir for firefighting and pool for SS men and privileged prisoners. The surplus of Zyklon-B left over after delousing at Auschwitz was around 3-6 times more to kill the estimated quarter of a million people during 1943. The claims of the pseudoscientific Leuchter report has been disproved: in reality, the concentration of hydrogen cyanide was too low to be explosive, diesel fumes contain carbon monoxide which can kill people, lice are more resistant to hydrogen cyanide than humans and the walls of the homicidal gas chambers has been exposed to the elements for many decades.

While a single eyewitness might be unreliable, multiple independent eyewitness accounts corroborated by physical evidence are very reliable. By failing to make this key distinction, Holocaust deniers are abusing and distorting cognitive psychology. Demographics and estimates of the number of people killed independently converge, making demographics estimates robust. The word “ausrotten” means exterminate when applied to living things, and no amount of rationalizations by Holocaust deniers will change this was some Nazis spoke of “ausrotten” bacillus or tuberculosis in the same speech and document as “ausrotten” the Jews. No serious person can claim that the Nazis wanted to put tuberculosis bacteria on trains and deport them out of the country.

This summarizes all the points made in the article. I'll go through them one by one and then get back to you once I've read through the thorough Leuchter Report debunking.

• moral equivalences are not an argument; I agree.
• Holocaust revisionists are actually Holocaust deniers; semantics and terminology, irrelevant.
• Holocaust deniers abuse the internal historical debate between intentionalists and functionalists in an attempt to spread uncertainty and doubt regarding Holocaust history at large by quoting historians out of context; this is a sweeping generalization fallacy and largely meaningless towards debunking individual claims.
• The swimming pool at Auschwitz was a water reservoir for firefighting and pool for SS men and privileged prisoners; the article states no documentation proving this, and it is a minor issue anyway. I'd be curious to see what the authors of this article would say about the movie theatre indoors, which Jews had access to and enjoyed according to certain Jews who lived in Auschwitz.
• The surplus of Zyklon-B left over after delousing at Auschwitz was around 3-6 times more to kill the estimated quarter of a million people during 1943; this section of the article was amusing. They make several estimates about what would be necessary for delousing train yards and barracks and clothings etc and arrive at a figure for leftovers which they then properly demonstrate could be used to kill 250,000 people. They argue the large amount of Zyklon-B sent to Auchwitz (the majority of it distributed at all) are indicative of using the surplus to kill. Yet only a fraction of the totals remain after their estimates "to be used for killing" -- that fraction is the safety buffer. It's basic engineering. Don't sent only what you'll need, send more than you could possibly need in case anything goes wrong. Since more Zyklon-B is needed for pests than people, as the article correctly states, that remaining fraction becomes considerably less of a "surplus" when it is recognized for the intended use of delousing.
• The claims of the pseudoscientific Leuchter report has been disproved; I'll return to this point after reviewing the other website.
• While a single eyewitness might be unreliable, multiple independent eyewitness accounts corroborated by physical evidence are very reliable; what physical evidence? It omits that part. And what of the large number of eyewitness testimonies that contradict the Holocaust that are supported by physical evidence. I mean the overhead airplane photographs where no extermination or signs of extermination are visible; the claims of a lack of visibility or awareness of any gas chambers, and pre-1945 photographs of Auschwitz without the useless chimney sitting beside the "gas chamber"; the insufficient doors ways for containing the gas; the lack of mass graves aligning with the number claimed dead; the number of dead in Auschwitz changing drastically as the years go on, decreasing from 4 million to a few hundred thousand as is accepted today, without the 6 million figure ever going down? That physical evidence aligns much better with the anti-Holocaust testimonies than any evidence in support of the claim.
• The word “ausrotten” means exterminate when applied to living things; the article admits it can be used to mean "uproot" as well, and yet they dismiss this as absurd, whereas I think it fits the situation perfectly. The Germans did want to uproot the Jews -- get them out of Europe. And they began methods to do so and would likely have had more success if not stopped with Britain and France's declaration of War.

That's all the article really supplies; it seems their debunking is easily debunked itself. And it mentioned nothing about how convenient it is that THE ONLY DEATH CAMPS WITH GAS CHAMBERS ARE CAMPS THAT WERE WITHIN SOVIET-OCCUPIED TERRITORY AFTER THE WAR. No mention of the evidence that the Auschwitz chimney was added after the war, no mention of the obvious holes in the Auschwitz gas chamber floor where plumbing (bathroom equipment) had once been, no mention of the marks on the wall clearly indicative of walls having been torn down, no mention of the total lack of formal calls from Hitler to exterminate any group despite the number of documents seized, no mention of the role Stalin played in covering up his own crimes by trying to distract the world with Hitler, no mention of the role Stalin played in killing millions in Poland -- deaths often attributed falsely to Hitler. No mention of so many crucial points! Half this article rambles on about how morally and factually superior Holocaust acceptors are to Holocaust deniers. A pitiful article all things considered.