Unconcerned and indifferent came to my mind.
Monica's answer reminds me of spectator, bystander, or onlooker.
From my personal experience: in a software company there are typically three roles involved in a code review process, namely author, reviewer, observer.
An author is someone who posts his or her code for review. An reviewer is someone who must review the posted code and take some action in order for the code review process to proceed. An observer is someone who has access to the posted code and may or may not want to take a look at the code. What's more, an observer is not required to do anything if he does not want to.
I would say the question raiser in OP's case is an author the moment he posts the question on the site, and later he becomes an observer.