If you use uBlock Origin adblocker you can put these in your settings (My Filters). One blocks by ID the other blocks by text match. ID's can change, but text matches will always remove the posts. Change 'poster-id' or 'phrase' as needed. Copy/paste to add new ones.
8kun.top##.reply:has(.poster_id:has-text(poster_id))
8kun.top##.reply:has(.body-line:has-text(phrase))