Algorithm changes affect each time legitimate websites more or less. Don't think that a new algorithm change is clean and perfect, because in fact it is not.
Algorithm change is a manipulation of data for returned queries, period!
Spammers are still up and running, copyright infrigments are still there, etc
The ironic "may day" update has destroyed much more than it was supposed to improve for websites and particularly small and medium e-commerce, affiliate sites, and many others. The update favorized big brands, and big marketers sites, what a neutrality joke!!!!!
Searchers do not have a better quality returned queries at all, that's a myth that Google try to sell.
Perhaps you should take a look at this link and you will discover that Google screwed up many webmasters: Google MAYDAY Update - SERP Changes May 2010