This is extremely depressing and explains so much about peoples' hesitation around file downloads.
I am trying to sell asset packs for game devs and a few have taken off in a major way or started to, but others are going nowhere, which may be because of the sheer distrust most itch users have of everything that isn't, as you put it, 'green flagged' by a ton of prior positive reviews and comments.
Social responses, genuine honest ones, are essential to everyone. If a thing is genuine, make a note of that and make it publicly known that the content is real. If it is not safe, if it is dangerous, post that negative response and report the scam as soon as possible. Warn people if there is an active scam in place and inversely, encourage material that is authentic.
Also, while curation in a censorship sort of form should not be itch's thing, maybe a battery of automated virus and malware scans should be in place for files people upload. It could help limit this type of damage even if it fails to catch everything.