> with absolutely no due diligence

But due diligence was done here - the blue check mark was checked. The user checked other people were seeing success with this. The user probably double and triple checked the bitcoin address he was sending to. He probably looked for the padlock symbol on the site he was getting the details of the scam from. He might have checked his computer for viruses and been using a hardware wallet with a really long password.

He just checked all the wrong things.