RE: Same content posted on both platforms| @botefarm account caught on the case of plagarism
As @papi.mati says, there's nothing to stop authors sharing their content on multiple sources. Whether that's Steemit, Hive, Blurt, their own personal blog or a journalistic magazine. So long as their content is original and self-written without plagiarism, they can share it as they wish.
If they are using the steemexclusive tag, then they're misusing the tag, in the same way that many users continue to misuse the club5050, club75 and club100 tags. Historically, hashtag abuse would prompt a downvote from big whales who wanted to bully smaller users but that feels somewhat unfair in my opinion.
If they are doing it within your community, you can ask them to stop. At very least, point out the misuse of the steemexclusive tag. This tag's used to help highlight posts for booming support so if you highlight it, then you're ensuring booming support won't come their way.
I am not aware about this but this is comes under the self plagiarism so I raised the issue
I understand the self-plagiarism angle when you're taking an old article, copying and pasting it as though it's something new or taking huge sections, etc. (like in academia).
I consider distributing it in multiple places at the same time more akin to a journalist publishing to multiple places or a more specific example - a press release.