Matt if you read hackernews. This is bullshit. Spam links should count for 0 value not negative value.
I've never met him, but as demonstrated by his long HN profile, Matt is clearly a nice guy. He's also smart, so he probably thought this exact case through. None of us outside Google really know how this works.
None of that means his group didn't make a poor decision in this case, but let's see if we can talk like adults and can learn more before going all "OMFG this is bllsht" on him...
In a sense he plays the role of a politician. Not able to do much (he is only one google guy after all) and trying to keep the masses feeling that he is acting in their best interest. He can't really be blamed. The bottom line is that none of this has any impact on google anyway.
If anything it simply pushes more people to want to pay for paid placement.
With penalties in place, those bad links might not be worth building because the penalties will outweigh the benefits of building massive amounts of low quality bad links.
https://news.ycombinator.com/user?id=Matt_Cutts
and he is quite active
If you have a better system let's hear it.
Still probably the right trade-off from GOOG's perspective, as long as black hat SEO has bigger negative effect on relevance than negative SEO.