Anyone can be fallible in the right circumstances. Maybe you're tired, unwell, in a rush, or otherwise distressed and not thinking straight. Maybe a malicious actor accidentally crafts a scam that coincides with specific details from your life. Perhaps the scam centres around some system you have less expertise in.

The point of not assigning blame isn't to absolve people of the need to have their guard up but to recognise that everyone is capable of mistakes.