I spend a reasonable amount of time wondering why some issues get labeled "culture war" and some don't, given that they are basically all the most important contested political issues. The "culture war" label is often (not always) meant to be dismissive, as if these are silly fights over trivial things. Sure sometimes they play out in The Discoure over seemingly trivial things, but that is true about everything.
Abortion is pretty important! Racism, pretty important! Rights of women, generally, pretty important! Fundamental human rights, pretty important!
There isn't one explanation, I guess, but today I'm leaning towards "issues about which many pundits secretly agree with conservatives but don't want to admit it."