There's nothing wrong with that. I'll let Will McAvoy of Newsroom (Aaron Sorkin) answer that for you. Take a look at one of the first season's episodes.
I neither suggested that conistonwater was lying, nor that there's anything wrong with Greenwald being an activist, just that we should openly acknowledge the latter.
When we say that people pretend something is true, we're usually implying that they're choosing to believe in their own myth, not that they're trying to deceive others.