I have read alot of great questions and answers on workplace, and usually learn something worthwhile. Out of all the SE sites I find myself coming back here most often, due to the high quality of questions and answers.
However, like any Q&A site, there are occasional unhelpful posts. Sometimes even counterproductive - for example "just quit" pops up alot. Although sometimes it's the right thing to do, we usually have nowhere near enough information to responsibly recommend that.
I also see "that's not your job" or "your job is X not Y", sometimes without enough information from the OP to support the assertion (and on occasion, flying in the face of the OP who has said "this is my job"), sometimes based on the job title alone.
This seems to be most common around questions involving software jobs - I think alot of us may be pre-loaded with opinions on those (myself included).
I feel that in many cases, this is unhelpful white noise. You wouldn't tell your boss "I don't need to solve this problem because it's not my job, some person on the internet said so". Not unless things were really bad!
Most of the time we won't have enough info to know what the OP's duties actually are. While there are definitely times (like when discussing coworkers that the OP isn't responsible for) where "that's not your job" is probably > 90% truth, this often can be translated into a more direct "mind your own business".
Do we think "that's not your job" is helpful? Or is it one of those things we should only say in the proper context with enough information to back it up? Or maybe it's no big deal?