Also, it looks like when a tag matched once, it will always remain, and cannot be reassigned from an abuse filter. This creates problems when the name of a tag is changed in an abuse filter, it won't be reassigned to the new name, new tagged edits are assigned to the first name (e.g. when Section blanking has been changed to section blanking on enwiki).

Maybe a way to solve the problem is being able to create tags on their own, delete them and rename them. Then one can choose a tag among the existing ones for an abuse filter.

Expanded on this at bug 18670 . Still the initial matter for deleting filters calling tags.

Fixed a related issue, but not the one you're thinking of in r51415.

However, tags which have been applied to edits should be shown in the interface, even if they are no longer applied. The solution to removing annoying old tags is to provide functionality for mass-removing and moving tags from edits, which is in another bug report.

To summarize: this is expected behaviour.

Change 81830 had a related patch set uploaded by Matmarex:
Show whether tags are active on Special:Tags

https://gerrit.wikimedia.org/r/81830

The patch above adds a separate column informing the user whether the tag is currently active or not.

Yay for reopening four-year-old bugs!

https://gerrit.wikimedia.org/r/#/c/81830/ needs review.

Change 81830 merged by jenkins-bot:
Show whether tags are active on Special:Tags

https://gerrit.wikimedia.org/r/81830