I'm not sure why that's the case, I can promise it's not, but I can understand if you don't feel comfortable downloading it :)
I actually had the same issue with one other game in the jam, I temporarily turned off my defender to download it, then just turned it back on right after.
Hey, I think I’ve figured out the issue. Due to Unity’s recent vulnerability discovery, Windows Defender may be blocking it outright. I’ve uploaded a new download that includes Unity’s patch for the vulnerability. Feel free to test that one :)