I also have a degree in Journalism (Broadcast Journalism) so, yes, I understand sensationalism has always existed within the profession. Hello, National Enquirer! It's funny because that was my mom's "favorite rag" to read and it drove my brother crazy. He's a managing editor at a major-metro newspaper, as well as a journalism professor. Truth in reporting has always been the number one issue for him when dealing with his reporters and students.
So while misleading sensationalism does and has always existed, it's a very different animal than what we are seeing now. You're right, much of the hate and misinformation is rooted in the internet.