thats common practice.. i knew plenty of companies in the past who did this, just so someone don't make a site trashing them!. oh yeah AOLsucks.com still exist. that was hilarious a few years back .
They have a huge list of owned domain.. According to domaintools, the owner of google.com associated with 235K other domains.
If I owned google, I would never care about it. In fact, they are working FOR you...negative marketing.