If a question is already tagged with shapely, ArcPy , PyQGIS, or any other spatial Python library then I think it is safe to assume that the programming language being used is Python and the python tag provides no additional information.
As long as its tag wiki has a language hint the syntax highlighting for any spatial Python library should already be set to Python and, if not, there is a simple process available to correct that at Any coding tags missing code language setting for syntax highlighting?
If we tagged every question involving a spatial Python library with the python tag then we:
- would already have about 10,000 questions tagged with something that is not specific to GIS
- may find that people stop tagging with arcpy, pyqgis, shapely, etc necessitating specialists in those tags having to open more questions before finding the ones which they are hoping to answer.
Extending your logic to some other examples, should we also tag:
- all PostGIS questions with PostgreSQL (which is used in many non-GIS applications)?
A "rule of thumb" that I use when reviewing tags on GIS SE is that if a tag is not GIS-specific then it should be used sparingly.
I think GIS-specific tags dominating our tags reinforces why our site exists and why experts in GIS and those wanting to learn about GIS would visit and join our community rather than try to build GIS sub-communities within other SE sites.