Sorry to hear about your bad experience on Hive.
As @kpreddy mentioned right now we only support posting either on hive, or across all chains together.
You can however disregard the votes/downvotes happening elsewhere.
You can even edit your post where downvotes normally take place and remove all the content.
We need to have the hive actifit posts to be able to find and reward our users with AFIT and votes across chains as our core infrastructure and voting happens there.
We are considering other options to give more flexibility to our users.