The cleanup proposal is part of the Structured Tag Cleanup Initiative, which includes closing, merging and deleting questions:
Step 3: cleaning up the tags, identifying close candidates, and the last call for heroic edits
During the two-week cleanup period, the community will be tasked with doing the following:
Cleaning up the tags: if a question is on-topic for the site, it needs to be revised and retagged with more meaningful tags.
Identifying close candidates: if a tagged question just slipped through the cracks and needs to be closed, it needs to be listed as a close candidate on the cleanup notice.
For any tagged closed question or close candidate, the cleanup period is the last chance to save them with heroic edits: consolidate lists into canonical answers and flag duplicate answers for deletion and substantially improve the quality of the question. If an attempt to save a question has been made, flag the question and list it as a "saved question" on the cleanup notice
STCI is well documented in that question, and I directed you in posting an answer there instead of posting comments in the specific proposal, as it seemed to me that you were contesting whether the initiative in itself had anything to do with weeding out questions that somehow don't belong. I felt it was extremely counter productive to post comments on specific proposal questions when there was a Meta question where you could summarize your concerns, as comments are ephemeral, don't allow for consensus, and are quite less visible than Meta answers.
Going through a tag is a great opportunity to clean up questions that don't belong to the site, for whatever reason. I agree that almost every question under software-engineering is on topic, however topicality is not the only issue with close worthy questions. Several of the questions that are identified in the closure candidates list fall under the not constructive category, but as I told you if you want to discuss specific questions feel free to ping me in chat.