We've poured countless hours into anti-abuse work on this site over many years, and still do. If you have some justification for describing HN as a "soft target", I'd like to hear what it is, because from my perspective what you call "there's no denying" is flatly false. Even your own statement contradicts it: if HN were such a soft target, it would already be completely gamed, which would make it a shitty site, which would make it an unattractive target.
I disagree that a significantly gamed HN would be overtly shitty. Influence campaigns work by posting engaging content that real users propagate. Setting the agenda is enough.