Are you sure? When I read this, it looked kind of like an admin being interested in improving MusicBrainz rankings in Google. So I have to assume that if storing links to spam/malware harms MusicBrainz, then we wouldn’t want to practice this policy.
How so? MusicBrainz pages can be used for tagging, following relationships, etc. Assuming we’re not talking about Internet Archive links, what can someone do with a URL that points to spam or malware?