Well, because we don’t have jurisdiction of the Bug Report forums, and we’re not part of the QA team. They do not traditionally post updates, acknowledgement, etc… The Bug Report forum is specifically to report potential bugs. It isn’t a contact point where you are intended to receive a response. QA takes reports from there and creates tasks to investigate the reports.
The only time you might see a reply from QA, which is extremely rare, is if they need to ask for specific information about something.