Precisely. There was a film early in the industry's history (Rasputin and the Empress, early 1930s) that depicted events from a real person's life in a very negative (and most importantly, false) way and the studio got the pants sued off them. Hence the disclaimer

edit: it was Rasputin! Here's a Slate article describing the events: https://slate.com/culture/2016/08/the-bizarre-true-story-beh...

edit2: Here is a secondary source from Stanford, which is drier, but also less subject to hyperbole: https://web.stanford.edu/dept/HPS/HistoryWired/Davis/DavisAu...