Yes, and if the people there were in any way acting rational that would be a possibility.
But it was established that the Sage System makes that mayor guy the exception, and people are pushed to be more easily aggressive and violent. Which is why the two main characters' skills blocked it.
It does not excuse their actions. They did leave at least four people to die, after all, and of them two are the MC duo and the other survivor is hunting them down.
...
Actually, that gives me a BIG question, that if it was answered in the manga I forgot:
Two of the girls in class clearly know Takatou's power. And in fact, they seem to know his full power, or have a close idea of it (they are using their phones to check on his seals, after all).
Why the fuck would they leave him behind?
...
Also, I'm still amused by his fake power's unintentional meanings.
"I thought you could only kill bugs!"
"No, I can kill weak insects," he answers, pointing over his shoulder to the dead dragon behind him.