This is a weird bit of advice. From my experience I have to assume you're saying "HR isn't the decision maker when hiring in elite tech companies" but the fact of the matter is HR/Recruiting is going to present the offer to most people, and it takes a career worth of preparation to move the conversation beyond that offer.
Well, I'm happy to have moved you a "career's worth" of wisdom forward in a single comment. You aren't negotiating with HR. HR does not know what you do, and HR's best idea of what you're worth comes from those ridiculous salary survey sites.
This is a cogent point. HR may be your point of contact for your salary negotiation, but they are not the decision maker or barrier. Ask for more money and they will ask someone else for more money on your behalf. HR is almost never the enemy in less-than-huge companies (and even then only moderately at worst).
