Why would anyone tell you not to write about what you know? Because that advice actually limits a writer's imagination. Hmm?!
The most recent article I read by Jason Guts can be found at bigthink.com/write-what-you-know-nil-the-most-understood-piece-of-good-advice.
The point of that article was not to draw upon what you know and write about events, but to draw upon what you know and write about feelings. Good stuff, eh?! Use your own emotions (or those you have witnessed) and give them to your characters.
Readers like that stuff, right?! I know I like a book that can express feelings in a way that come across as real.
So once again, write what you know, just put a little emotion into it. I know, I know. Easier said than done, but it will be worth it!! Happy Writing and keep it real!