That's a valid viewpoint. There is a way as a poster to create a post with rewards declined. It is up to each author to decide if they want to post that way, but based on what you are saying it sounds like something that you would want to do if sharing that type of content.
Your question is a really good one, and I don't know the answer.
I could be wrong on this, but I would expect that when a website like Steemit (or Facebook) shows a YouTube video - that it still counts towards the original YouTube poster's views and advertising revenue (assuming they have it setup to monetize). Sharing the link on somewhere like Steemit or Facebook is still helpful to the original poster in that sense.
Whether it is ethical for someone who shared a link to the content to get paid for sharing it is a very interesting question for the community to decide.
You should think of writing a post about it. I think it would make for a good discussion.
Thanks for telling me about the option to decline payout.
In the past, I have seen videos from creators on YouTube complaining that Facebook steals their rewards. I don't understand how that happens, or if it was ever corrected on Facebook. As far as I understand, who gets paid depends entirely on how a referring platform is designed. I have no idea if steemit is programmed correctly or not.
My wife is in the process of dying, so it will probably be a few days before I feel up to tackling an article about this. Thanks for the comments!
Sorry to hear about your wife :(