I don't think advertising is inherently evil (though I respect that some may disagree), I think the problem is that we're still in the early days of Internet advertising. The technique isn't quite there yet.
Examples of passive ads: music discovery [pandora], news aggregation [HN], etc versus active ads: traditional ads (TV/radio/internet/magazine) and active product-pushing.
As an aside, I am aware that Pandora has ads which is kind of mind boggling - they are actually providing free advertising to the music companies by letting me discover new music, yet they still have to pay royalties, so they are forced to use ads.
Maybe in the advertiers' and their bosses' deluded minds.
I'd estimate that 90% of ads I saw were lying either directly or by omission. They don't add value, they try to trick you in to buying crap you don't need, that's often no better (or even worse) than the competition, products that can even be harmful (like various prescription drugs that you'd often be better off not taking in the first place).
The people that peddle this crap are slime. But I'm not at all surprised that a large contingent of HN members would defend them and try to justify their miserable, lying, parasitic existence. After all, many of them own companies which depend on advertising. So they try to apply some moral balm and pretend that they're "adding value".
However, I don't think it's fair to say that "HN members defend them" since (as of this comment), there is a 2:1 ratio of blockers vs. non-blockers. OTOH, this survey doesn't distinguish users who block ads AND use them on their own sites.
Ads generate $billions online. They work.
1% of the online population block ads. It's not really a problem outside places like HN where the majority detest ads.