I realise it can be a bit difficult and confusing to understand how this eco system works. It is SO different to the way that mainstream works that it will take time to get used to not having rules laid out. It may seem confusing and frustrating to not be able to find the rules in one place.. and that is because Steemit is a somewhat Anarchic eco-system. It is run and governed by the people, and operates by consensus.

Therefore, the best way to understand what is OK and not OK is to ask the people here, rather than try to find the rules or rule book. What is considered acceptable changes, depending on the issues that people are having in their day to day activities. In the case of plagiarism on the FP tag, there is a low tolerance due to the volume of copied posts aimed mainly at getting rewards.

So, the consensus on tags is generally that if you use a tag that you have started yourself, you may decide who is able to use it and how. Since the #familyprotection tag is a reward based endeavour, the FP team have to decide how to handle posts to ensure that their aims are being met. They have to discourage certain posts so everyone gets the message, and likewise, reward the good ones for the same reason!

I hope this helps you to understand things a little better