Opera isn't in the repos either, but I see no reason to complain about it. Both Chrome and Opera is very easy to install on Ubuntu if you want to use them. It would have been altogether another issue if the only way to install them was by compiling the code, adding a PPA, or something along these lines.
Now, regarding the tracking and privacy concerns... As a person who is very concerned about privacy, there certainly are some features in Chrome that worries me. http://en.wikipedia.org/wiki/Google_...#User_tracking For instance, when using the omnibar you are talking to Google's servers, although the data apparently is anomynized. However, Chrome isn't tracking you more than their search engine. What it boils down to is this: do you trust Google enough to use their services? If you do, then Chrome isn't worse than Google, and if you don't, then Chromium certainly is a brilliant alternative.