What is the difference between handling spam flags for serial posting?

I suspected one user's serial posting as spam and raised 5 spam flags. 1 of them is marked helpful while 4 of them is declined.

This is the answer that is marked as helpful, which I leave my observation as comment:

I consider this as spam by lack of disclosure of affiliation, rampant posting and likelihood of being LLM-generated

But the other 4 posts that are sharing the same observation are all declined spam flag.

1. stackoverflow.com/a/79966757

2. stackoverflow.com/a/79966802

3. stackoverflow.com/a/79966822

4. stackoverflow.com/a/79966843

I cannot locate the difference between the helpful flag and declined flags. May I learn how the moderation decision is made and what guideline should I follow in the future, please?