For example, ANY shop, of ANY size, is going to have issues with tricky-but-hard-to-reproduce bugs. The parent comment is highlighting the fact that they can't be sure if this sort of prima donna is going to be willing to run that issue to ground, or if they'll put up a stink about it being "boring".
Additionally, even if this person were working for free, there's a definite cost to foisting difficult bugs on your teammates.
Do you honestly believe only "cogs in a machine" should be / would be interested in fixing that sort of issue?