Here I thought “ignorance of” and “disregard for” seemed like they would be good fits. I didn’t really understand why “disdain for” and “disregard for” would be better because, to me, disregarding something would be akin to ignoring it. But if one would have disdain for something, does that mean they disregard it? I didn’t necessarily think so.
Putting ignorance for and disregard for in the blank does not produce sentences that mean the same thing.
Ignorance of does not mean ignoring it. It means being unaware of it.
Disregarding it = knows about it but chooses to ignore it.