akuperma,
What the DNA has shown, that is significant and was very disappointing to secular Jews (who don’t like being Jewish), is that Ashkenazim are not descended from diaspora converts but are from the same “stock” as all the other Jews (so much for various theories that we are really Turks from Central Asia, or some other such ancestry untainted by Jewish blood).
While there are ample things done and believed by secular Jews at which we can take umbrage, I have never heard of the Ashkenazim-are-all-descendants-of-Khazars ridiculousness being promulgated by secular Jews. It’s usually espoused by anti-Semites and anti-Israel extremists.