There is a good technical reason why this is done (Score 3, Informative)

Google is obsessive about reducing HTML size for fast delivery, and that explains two of your observations.

The JS obfuscation is code reduction - all the variable names are replaced with a single letter and the white space stripped in all of google's JS code to reduce the script length (though no doubt they like the fact that this makes reverse engineering hard too.)

Adding the events after the page loads means you can loop over the array of links returned by document.getElementsByTagName("A"), instead of adding the handler as text to every link.