I'm not sure about this. It almost sounds like Google is posturing. The reason I say this is that while Google was getting bombed up until last week with scraper sites, Bing wasn't.
If Bing was really copying results, they would have reflected the spam sites, because people click on those when they are highly ranked just as often as they click on the originator site. After all, the problem is that the content is identical.
Well, the article suggests that there is more to it than just mere copying. The way I see it, Bing is basically taking a look at what is that the user does when it searches for a term that is unknown to Bing. Once they have this initial data, they are able to filter it as they see fit to avoid getting spam results.
The allegation is that Bing is/was copying results for long-tail queries. The specific example being some very misspelled words. So in no way is the claim made that Google and Bing results are identical (even for most of those long tail results, given that it's only the top ranking pages).
If Bing was really copying results, they would have reflected the spam sites, because people click on those when they are highly ranked just as often as they click on the originator site. After all, the problem is that the content is identical.