Google has an undeniable monopoly on search, and a near-monopoly on web browsing software via Chrome and its forks. And even alternative browsers such as Mozilla’s Firefox reference Google’s Safe Browsing service to decide on the trustworthiness of downloads.
Stopping the spread of malware is a laudible goal, but a consequence of this is directly harming free and open source software developers from being able to release their software without paying expensive certificate authority rent-seeking fees.
This isn’t just a scary warning that is easily ignored: web browsers will warn users that your software might be malicious. And it’s clear from Google’s warning that it considers your site compromised, which can lead to search result penalties including delisting.
This in spite of the fact that you’ve done nothing wrong other than release software onto the web.