why does everyone want to disconnect ashkenazis from their jewishness

There are plenty of theories/opinions out there that ashkenazis are somehow fake jews or just white people

One reference I have seen from people is by saying since isreal has high skin cancer rate it means that ashkenazi jews are not native to Israel

I would like some clarification on the origins of ashkenazis. The story ik is that ashkenazis were exiled and now live in Europe