It seems to me that the studying is focusing on the extent to which the life of mothers affects the life of children, particularly looking at multiple stages of life including menopause whereupon the mothers of mothers can directly contribute. It isn't really about K vs. R, but rather understanding that primate mammals are already type K (investing more heavily in fewer offspring) what the effects of self-preservation on the mother are.
Regarding the comment on "weird conservative 'women are for breeding' undertones"
That seems like a strangely anthropocentric viewpoint. For most primates other than humans, breeding and childrearing are dominated by the females because the successful strategy for males is often to try to impregnate as many females as possible, and the successful strategy for females is often to try to have sex with as many males as possible to help reduce the chances of infanticide.
It was with the homo sapiens larger brain and the greater negative effect on females that cooperative reproduction strategies became particularly important.