We talk a lot about it, but sometimes I think people forget the point of it. There isn't actually any bothsidesism. What we actually have it a mainstream press which will find any way to legitimize Republican candidates as mainstream - no matter how much they lie, no matter how racist or sexist they are - while not offering the same "consideration" to Dem candidates. In 2004 the press had no trouble monstering (a British press term) Howard Dean over something ridiculous. They couldn't even bring themselves to monster Trump when he said mean things (and they were genuinely horrible) about the patron saint of the Washington press, Saint John McCain. Sure they harumphed and said "Trump is dooooooomed now!" which was silly. But it might not have been silly had they chosen to monster Trump over it. Whatever one thinks of McCain, the comments were pretty disgusting. If they'd run them on a loop 24/7 as they did with Dean, it might have actually had an impact. And it's not as if there hasn't been plenty of other material to work with. Now it's just oh, well, Trump is Trump just let him be.
Both sides don't do it, and the press doesn't treat both sides the same.