If you are comfortable with the "developer tools" for your browser you should be able to find the actual URLs for the videos; they are in a <video/> link inside an <iframe/>. Sending take down notices to rec-tube is likely a waste of time, but I took a quick look at the site and the videos I examined are stored at a site called fileurl.link, which seems to be owned by OVH.fr, which (I believe) is hosted on Cloudflare. OVH and Cloudflare both take DMCA take down notices seriously so sending the fileurl.link URLs to Chaturbate may yield the best results.
I do link scraping for a group of content creators so they can generate DMCA take down notices, and targeting the file host rather than the pirate site has proven to be very successful. Maybe I'll script up scraping this site as well...