[joenot443]

I don't know if you can speak for the entire left here, it's really not hard to find articles from the 2010s from otherwise fairly respectable progressive publications which are pretty confident. Usually when I've heard ideologically minded people talking about "transgenerational trauma" [1], it's from a lens of epigenics. I don't think anyone would reasonably doubt that wealth or poverty ripples through many generations, the idea which I hear touted pretty frequently (and is discussed in the article), is that past trauma from war, famine, racism, etc. has a biological mechanism which explains disparities we see today.

As others have pointed out, it's a super convenient conclusion for folks who seek to understand the world in such a way, but at least presently the data just isn't there.

[1] https://en.wikipedia.org/wiki/Transgenerational_trauma