These scholars don't came up with stuff from nowhere, but build on hadhits from the prophet, the bidacah categorisation is build upon this hadith:I said the prophet said, you say Imam Nawawi said. The people you’re referring to are hardcore Hanbalis, the same Imam you’ve quoted as approving ‘good innovations’. You’re pasting text you don’t even understand. You’re like a donkey carrying books.
Then he (ﷺ) said, "Whosoever introduces a good practice in Islam, there is for him its reward and the reward of those who act upon it after him without anything being diminished from their rewards. And whosoever introduces an evil practice in Islam, will shoulder its sin and the sins of all those who will act upon it, without diminishing in any way their burden"