The Middle East Media Research Institute is an Israeli-US effort that deliberately mistranslates or otherwise misleads with a bias towards Israel. Assad didn't doubt the existence of the Holocaust nor that 6 million Jews were killed. He did state two problematic things, however:
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Speaking imprecisely on the extent to which Jews were targeted when trying to draw attention to the fact that Germans used the same concentration camps and mass death on an even larger number of non-Jews.
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Delving into the Khazar origins hypothesis for Ashkenazi Jews, which was originally based on scanty evidence and is now an academic quagmire in terms of genetic evidence. The real reason for the hypothesis in these situations is to undermine the idea that European Jews are a diaspora from The Levant in order to undermine Zionist claims to the land, and to that end it's a counterproductive overreach, as it rhetorically implies that a 2000-year-old diaspora would indeed have the right to settler-colonize and brutalize the populations living in "the homeland".
Both are in the spirit of lazy narratives that flirt with antisemitism but are not the naked antisemitism that the headlines are falsely claiming.