My best guess is someone may have reported it. Most indie games trigger people's anti-virus software even if the game files are 100% safe. If I had to make an assumption, I'd say someone's antivirus flagged the game, the freaked out and reported it, and because your account is so new, itch.io quarantined the game as a precaution.
I could be completely off base tho, so take the above with a grain of salt