Low-IF journals are easier to publish to by definition. You first try to publish in a high-IF journal, if they reject you then you try one with lower IF, and so on. I'm all about not taking IF as face value and don't need a n-th reminder about the metric's issues seeing how rehashing them is something of a favorite pastime among scientists, but in this specific case other more qualitative assessments don't line up either:
-Journal is completely obscure to the genomics community
-No causal genetic mechanism is shown, everything is shoved into a "heritability" black box that some people seem to think is like your video game character starting stats or something
-Authors don't have a genetics background
-It's not my field, but there appears to be a wealth of literature on how fertility rates decrease in history, none of them involving "heritability" and little is done to address, reconcile or unify that
-There does seem to be darker political overtones that are exacerbated by commenters, leading me to think the arguments are not being made in good faith
Journal IF is just a (flawed) heuristic but in this case it sets a low prior and the "updates" didn't help