It feels almost random for what gets removed and what doesn't. I've combed through all the pinned posts and guideline material, but even then I'm still left baffled why my posts are deleted. Many had already gotten approval. I just fix a typo or a mistake and I come back to find they've been removed.
For the most recent instance of this, I think I know the cause. A similar post to mine was made and approved somehow after the time I made mine, so when I edited mine whatever goes through all the to be approved posts falsely labeled mine as a duplicate of the duplicate post and deleted it.
The volatility and lack of communication really makes it discouraging to use the Minecraft feedback website.
This isn't anything we can help as as the feedback website is community moderated.