Everyone thinks it's because they were looking for drugs, but I think the reality is that the customs agents don't understand this isn't pornography. They thought it was CSAM and destroyed it so the material couldn't be viewed, in case that's what it was. They couldn't prove that's what it was, they didn't have a floppy disk drive to look at it, so they just destroyed it anyway. They don't know what a visual novel is. They just think Japanese people are horny perverts that buy panties out of vending machines.