Your points about the entitlement of hippies is disingenuous. Max Yasgur wholeheartedly allowed Woodstock to happen on his property. Paid workers helped clean up the aftermath as well as volunteers.
"Is it okay if we use your telephone?"
To which the man answers that the phones are out. To which the hippie replies,
"Water?"
You might think this the source of the "Get off my lawn" and similar references people on HN use. I mean, what could be more of an embodiment of entitlement?
But what does this townsperson do? You should watch the documentary to find out. But I'll give you a hint-- it isn't to say, "Get off my lawn." Nor even, "I'm conflicted because on the one hand this is now a national disaster area, but on the other you knew that if you and 100,000 others come to a small town and stress the infrastructure there was a possibility that this could happen, and I wouldn't want to set a precedent of..."
The individual concert-goers didn't know there'd be far more people than expected and that local infrastructure and the organizer would be overwhelmed.
They saw there was a concert and decided to go, just like every other show anyone attends.
Upon arriving, they were stuck in a situation they didn't expect and which people don't expect when they head to a large event that's supposedly "official" .
At that point (gridlock, overwhelmed infrastructure), they're without any options beyond asking others for help, because they weren't prepared for a situation that shouldn't have happened. They came to attend a concert, not a survivalist retreat.