Regarding the surging of the gate - that video looks like it was taken in the middle of the day, and this event was happening past 9pm. That is potentially 3 hours+ to reorganise security around the main stage to account for a potentially over-limit crowd.
As for Travis, I can´t say what he did and didn´t incite. Perhaps he could and should have taken the initiative. But surely the onus is on the organisers and security to pull the plug on the show, not the performer?
Finally, I have been at gigs and festivals with people passing out. It is not that uncommon. In fact I remember my first ever gig at the O2 academy in Liverpool. It was a Motorhead gig, and although the venue was not overcapacity, as soon as Motorhead came on everyone who had been on the balcony section for the support acts came down to the main floor without anyone seemingly stopping them. Me and my mate were at the bery front. I saw two people crowdsurfed out unconscious, and both my mate (who couldn´t breath) and then me had to be pulled out at the front as we were getting crushed against the barriers. I just took it as normal at the time, even though I was only 13/14 at the time and was slightly shook up at first.
So yeah these things can and do happen, and are nearly always easily avoidable with some better organisation. As we should all know.