The neutral tag will be even less impactful and still take an equal amount of time that could be used to (instead) report posts.
I don't mean about instinctly shitposters whom mostly never change their posting habit, but you know what? There are real users, whom simply don't familiar with the forum, posting shit in their first days in the forum. For those kind of users, whom have good progressive attitude to change, like me, such neutral tags might help them to realise their faults, and they will change.My neutral tag, years ago.
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This user is a garbage shitposter who writes redundant posts in shitty English.
After received such neutral tag, I was shock, and collected these English books to improve.Collections for someone who would like to improve English skills
To conclude, neutral tags on shitposters make sense (kind of help), if you have time to do it.