They could, but looking at the sheer number of posts and threads being added each day (sometimes even about the exact same bug), do you think any moderator wants to invest more time in making sure that each reported bug has been approved from a ‘somewhat’ official source, instead of reporting these bugs to the developers themselves or adding them to the internal database / noting them down for re-view?
Spending more time on assuring the approval of each reported bug, than actually working on fixing those bugs (or at least noting them down) is very contra-productive for the project as a whole (even if said moderator(s) are not in direct contact with the developer team).
I’m sure the Devs don’t miss any submitted bug, they just don’t come in and say how happy they are that you added something relevant. 
No offence.