They'll turn eventually. Google is great at the moment and will continue to be such for some time I think, but once a company gets big enough lawyers and HR types start to infect the organization and the clock starts ticking.
And when they do, they'll have all these patents!
edit: To clarify, I think it was a good idea they got these patents, but as for being used offensively I think the question is "how long until" rather than "if".
IBM, with over 45,000 patents, could easily and completely shut down every single aspect of the technology industry if they wanted. The fact that they haven't in its 100 years is a testament to the clearly more superior way of competing in the market to win out.
And on the other hand Intellectual Ventures set out to provide a mechanism for preventing patent abuse by letting small companies use IVs patents to protect themselves yes have turned out to be the biggest trolls going.
It's all supposing and it could go either way but early intentions only count for so much.
I'd like it if Google held their principals but it's hard to look at them and not see their principals eroding just a little bit over time and wonder if this might be one of them.
After all, they have a relatively weak portfolio right now and you could argue that their lack of offensive action to date is as much a case of them bringing a knife to a gun fight as a matter of principal.
Call me an optimist, but I don't see it happening with Larry in charge. Sure, they'll countersue Apple/Oracle/whoever, but I honestly don't see a Larry-run Google attacking competitors with patents outside of countersuits.
And when they do, they'll have all these patents!
edit: To clarify, I think it was a good idea they got these patents, but as for being used offensively I think the question is "how long until" rather than "if".