No, I do not think it is abuse to put up the exact same post both on Hive and Steem. That practice is called cross-posting. Who or what would be the victim here? Stakeholders of either blockchain? If your content is not abusive itself, then why on Earth would it be abusive for it to be posted to both Hive and Steem? Do the stakeholders of Hive or Steem stand to lose something if a piece of content is posted to both chains - assuming it is not a case of plagiarism? Of course, not.
If you share links to both posts on the same Discord group, that can only be abusive so long as such links are not welcome on that particular Discord group.
You can access the Hive blockchain by using several different Hive front ends including:
For more info on HIVE: Hive - The Blockchain & Cryptocurrency for Web 3.0
Join the HIVE Quora Space: The Hive