Yes, I have always wondered why this happens the way it does. I haven't experiences being redirected through them, but it seems that on logon one is being randomly selected. They all are in the same 216.58.212.* subnet (now and here) but each have distinct IP-pairs.
Might it be some attempt to disspel censorship, such as the scenario you're describing?
On a slightly related note, I really hate that we Internet Citizens are convicted to using plaintext server name indication.
