For the sake of argument, you could say it's about the right people "touching" your software, especially if you dual license it so that people who don't want the unpleasant AGPL terms pay some money for the benefits they're receiving.

After all, cloudkick doesn't seem to mind if some people don't touch it with a ten foot pole because of the price.

I think it's a tradeoff: with GPL style licenses, you risk excluding potentially valuable community members who use your code in their own proprietary applications, but may give something back. On the other hand, sometimes those people/companies give nothing back, and some people find that irritating.