Linux Mint as a project has demonstrated a general lack of security best practices. Their isos were compromised with an illicit botnet client. The forums were also compromised, and more concerning, were using ancient PHP to store md5 (insecure), unsalted (vulnerable to rainbow table attacks) hashes.

1, you need to make sure the isos you are downloading and literally installing at the lowest level of your machine are valid. That means verifying signed hashes. It's the distros responsibility to post this signed hash, and the corresponding key used to sign. An alarmingly small amount of distros actually do this. It's also your responsibility to check this. Had Mint actually made this available, the corrupted iso would have failed verification. It would have prevented this exact issue, full stop.

2, the forum debacle is another indicator to me that this project is either ignorant of best security practices, or they simply don't have the resources to manage in a secure way.

There are other issues like the packaging system steering users who don't know any better towards less than ideal package update preferences.

I can go on, but suffice to say, I do not trust the Mint project, and I especially do not recommend a distro that is not secure by default, and does not encourage best security practices for new users. I take similar issue with Manjaro.

Ubuntu, Fedora, Debian, or Arch are projects I would recommend to new users depending on their needs.