Why do some JWs love seeing others get disfellowshipped?
Because in a perverted way it makes them feel superior.
Jehovah's Witnesses believe they are the only true religion. They have God's blessing and no one else does. They are doing God's will and no one else is. They will be in the New System and no one else will. Etc, etc.
For some of them the feeling of being superior doesn't stop there and they eventually begin to "cannilbalize" each other in the sense that they take pleasure in another being brought down, even one of their own. Most wouldn't let it show, perhaps even appearing to be heart broken about a disfellowshipping, but the feeling is there.
"So and so is disfellowshipped and I'm faithful."