Are you talking about the Itch app itself or about downloaded games?
Because, well, there is malware uploaded to itch daily. So much, that it often gets indexed and appears along the regular games. There are even cases where the fake will appear alongside the original in a search. The current methods used by Itch to deal with this are not up to the task - we can regularly see hacked accounts used to spread more malware.
What makes this even worse, many indie games do provoke false positives in scanners. It is a honey pot for any scammer. Users that expect such things naivly downloading the new shiny games. There are literally legit games where you get told in comments to ignore your anti virus.