Booing isn't racist, monkey chanting is. What I heard last night was mostly monkey chanting, it was clear and audible. The cameras even showed a group of them doing it.
Whistling during national anthems is disrespectful but shouldn't be punished in my view. England have been charged with this and not having enough stewards. It's almost as if UEFA are trying to even it out. I didn't see any security escorting these guy's out last night, they just seemed to walk out in their own. I also didn't see that many Bulgarian stewards