I'd wonder who else she was hearing about BF from, tbh - has she got another friend or work colleague who didn't BF and who's helpfully(!) warning her against this 'BF mafia', pressure, etc. - in my experience people don't get that from nowhere, they hear about it from other people, and once primed to expect it, see it everywhere... I hate the fact that once you gain any BF expertise at all, even enough to be able to point people towards sources of help, your motives are instantly suspect.
If it was my friend, I might draw the analogy with labour with her - say that both are natural processes that sometimes need help, and that the reason the BF rates are so low is that a lot of people don't realise that it's not necessarily straightforward, and that there's a lot of value in the practical help that's available. I'd try to make the point that quite small practical tips can make a huge difference. If she's cringing at the idea of talking about these things with people, can you point her towards kellymom, as a place she can go and look completely on her own?
I might make the point that although her HV may be annoying her, she may actually need to be being wary of her in a completely different way - as someone whose BF advice may be well-meant but wrong. Perhaps you could agree with her about things like too much pressure being bad (but steer clear of your opinion of why certain things aren't pressure, but help), but then go on to discuss how much better than that sort of vague pressure is the basic, practical (that is to say semi-medical, relatively objective) information. So perhaps she can start to feel less like as an overall 'BF-world skeptic' who's having to throw the baby out with the bathwater, and is rejecting the undifferentiated mass of BF discourse that's out there, and feel more like just a BF skeptic who's rejecting the wishy-washy 'pressure', public discussion of nipples etc., and the poor information of some health professionals, in favour of using her own intelligence to sort out the information she needs. So in a way you would be agreeing with her strongly that she should be left to get on with it, but also encouraging her strongly to get a good personal information base in place for the tricky bits which, just like with labour, can crop up for a few people and may really affect the outcome. And maybe occasionally she will want to commission help from someone more expert, but on her terms. So perhaps she can really feel that she's owning her breastfeeding experience, and driving it, she's not following someone else's line, and isn't having to sign up to any earth motheryness, while still being open to the best practical, basic, information. She sounds a bit like someone who needs to believe that there are objective, biological reasons for some of the BF information out there, because she's going to be hugely suspicious of anything coming from a LLL or similar source (even if it's the same information).
It does sound difficult - good luck.