Because I have actually seen these things. If you right click on one of your images, and select search for similar image on Google, you will be taken to a page with hundreds of links to fake news sites. Pass through them, and find a link to a site for scientists and engineers, and you will find the origin of the photos. They have simply been taken out of context.

Here is a link to a non-technical site where such equipment is discussed. If you watch Discovery channel you will also see such equipment from time to time. The barrels are filled with water to stimulate passenger load during aircraft Air Certificate worthiness trials.