Legal questions about software licenses are off-topic. The gpl tag should be burninated.
The beautifully concise licensing tag currently says:
This tag should be used for questions about software that provides licensing services, such as a licensing server or client. Don't use this tag to ask for legal advice about licensing.
On the other hand, the unlovely gpl tag is currently just a description of the GPL itself, with no indication of how the tag could be used as an on-topic question about implementing software.
If there is a way the tag could be used in an on-topic fashion, then its tag wiki should be updated accordingly. If not, then please annul this tag faster than a drunk Vegas wedding.