Research Gate should block repeated requests for free downloads of copyrighted material, once the Author has declined to give away his/her work for free.
All of my books are copyright, I worked unpaid for years to write them, and people should legally purchase them if they wish to make use of them.
Research Gate is encouraging people to think they can obtain my work without paying anything to the author or publisher. There are Pirate sites that make that easy for those with no morals. Research Gate - are you facilitating that?