You're hitting multiple separate topics here, though you dont' seem to realize it.
1) Themes and Plugins do not phone home. Period. None of them do. A 'powered by' link is not a phone home, per sey, it's a link. I should have been more clear. My bad. ETA: Exception. If a plugin is acting as a service, it's permitted to phone home to provide the aforementioned service.
2) Themes are permitted to have one public facing 'Powered by' link. Plugins are not unless you opt-in.
3) WordPress core does transmit data back to home, but that's in order to y'know, let you upgrade themes, plugins, and core, from within core.
So as you see, there are three separate points here. If you're complaining about the third, I shall quote Otto from 2 years ago:
The WordPress version is included in case the response format changes, so it can send back the right responses to the right WP versions.
The locale you are using is sent to send the correct language data back.
The versions of PHP and mysql you are using are used to create aggregate data information about how many installs use PHP5, etc. For example, they've said that about 11% of users still use PHP4. This info tells the developers which versions of the software they need to support in the future.
The blog url is a unique identifier for each site, so that the statistical information can be correct. Otherwise you wouldn't be able to get accurate percentages, since some sites might check more often than others.
All the plugin information is sent so the server can determine which plugins you have that have updates available for them. Sending just plugin name and version number is not enough, the plugin name and version and description and such can all change, there's no unique identifier. So the update server uses a fuzzy match method, to try to figure out what plugins you're asking about compared with the plugins it knows about. Ditto themes.
No hypocrisy going on. There's a lot of information going on, and it's easy to miss one thing in the mix, but really, we're not contradicting here :)