As long as you cite your source on the video and explain that you're using to support what you are saying that is not plagiarism. It's more the blatant plagiarism that get people in an uproar. Anyone can go to any webpage copy and paste everything on the page and put in a post and try to pass it off as their own. There is a bot #cheetah that tries catch things such as that. However that is where we as a community need to do our due diligence and not simply upvote blindly. If you haven't yet read the Whitepaper in the right menu it will give you some help in that area.