Regardless of how you feel about being racist, some people will accuse you of being uncomfortably close to a Nazi for talking about the Yamnaya Y line taking over a continent, because 19th and early 20th century anthropologists that the Nazis liked and amplified the ideas of really did think that the Yamnaya Y line took over a continent, they just called them "Aryans" instead of "the Yamnaya Y line".