How does one bulk-remove a tag?

You can do an advanced search in the contacts list page to narrow down all the contacts that need to be edited, then click ‘Edit All’, then ‘Remove a tag’

Alas, this did not answer my question.
😦

In the meantime, I have jerry-rigged something whereby

1. we can use the bulk API to bulk apply a tag named e.g. “delete-tag-FOO”
2. implment an automation which is invoked by delete-tag-FOO and removes FOO as a result

This is of course not a general solution and it seemed to work for a week, and now bulk-tagging seems to have mysteriously stopped working 😦