The late 19th century saw the emergence of the theory that the core of today's Ashkenazi Jews are descended from a hypothetical Khazarian Jewish diaspora which migrated westward from modern-day Russia and Ukraine into modern-day France and Germany. Linguistic and genetic studies have not supported the theory of a Khazar connection to Ashkenazi Jewry.
From your source
Linguistic and genetic studies done by who exactly ?
Well of course there are some "studies" claiming COW-ID "vaccine" is safe.
By linguists and geneticists.
https://forward.com/opinion/385706/the-khazarian-hypothesis-is-not-the-only-junk-science-origin-story-of-jews/
https://forward.com/opinion/382967/ashkenazi-jews-are-not-khazars-heres-the-proof/