Eric Winston is NOT lying in that it did happen! I was there too, and at least 50 other Chiefs friends were there who also will attest they witnessed fans reacting happy about Matt being hurt! We were all in different sections throughout Arrowhead!
No, it wasn't 70'000 fans, but I'd say judging from experiences of those who witnessed/heard it...it was at least 1/8 of the fans at Arrowhead who celebrated Matt's injury.
It doesn't matter how many did it, the point is there were enough of them who did that it felt like the entire stadium to an upset Eric Winston at the time! He wasn't the only Chiefs player who observed fans celebrating Matt being hurt. Also, Ravens players heard it too, & a couple of them spoke up saying they found it appalling, not right!
So...you have Chiefs & Ravens players, as well as 1,000's of fans who witnessed it besides Eric. It depended upon what part of the stadium you were as to what you heard. Many in upper level don't hear the crowd noise or heckling in lower level, vice versa. Not all sections had fans behaving that repulsively, but some did, including mine!!