The blog post discusses a specific issue with PostgreSQL's query planner related to the use of Common Table Expressions (CTEs), LIMIT clauses, and the RETURNING statement. It highlights how certain query structures can lead to ambiguous execution plans, particularly when deleting rows. There is a significant concern about undefined behaviors and the risk of deleting multiple rows inadvertently due to query optimizer decisions. Users express confusion about the lack of clarity in the author's explanation, emphasizing the need for more straightforward practices, such as avoiding potentially ambiguous constructs, and the consideration of proper alternatives like using `= ANY` instead of `IN`. Additionally, there are insights into the necessity for better detection methods for such ambiguities through linting tools or CI checks to prevent unexpected results in production.