If you want to give feedback about the video on facebook, it will go to facebook organization. Not the post owner. So be careful.
However if you want to do this then click on the three dots placed at the right corner of the post. It will show you multiple options.
Clicking on the feedback button, will show you options for different categories for which you want to give feedback.
You can choose any which suits your feedback. This reponse will be forwarded to facebook owners and they will react accordingly.