Yes, that makes sense. But I don't think itch has the resources and finances to check every file, especially manually with a specialist.
Has it really happened in your practice that viruses ended up in game files?
Viewing post in Only browser games are allowed and no exceptions?
Not our Jams specifically (thankfully), but it has happened in other popular Jams.
This measure is mostly a preventative one.
Try to imagine being in my shoes where some hacker could ask the same questions you are and then post a malicious executable and have a bunch of peeps get Malware/Ransomware and greatly inconvenient peeps.
There would be less trust in our Jams and therefore less turnout.
All it takes is one unfortunate incident to remove trust.