This topic has been raised previously on individual site metas, but I observed it as an issue on main Meta as well.
Ordinarily, holders of gold tag badges have the privilege of "dupe-hammer" (binding VTC vote as a duplicate) on questions that have a tag they have the gold badge in.
The rationale for the privilege is that, for a subject matter tag, having a gold badge is indication of subject matter expertise, and thus likelihood that the holder is expert enough to figure out if something within said area of expertise is a duplicate.
However, this rationale breaks completely for discussion meta-tag on Meta sites. There are no "experts" in "discussion", as a subject matter topic, and therefore nobody is 5 times more qualified than an average VTC-privileged community member to decide whether something is a duplicate just because it is tagged as discussion.