People need some rumor control and exercise some mental restraint in not assuming what is or what might be going on. Generally, with a shortage of reliable evidence otherwise, applying a slight positive bias is safe. It isn't as if finger wagging, being a moral scold or adopting a 'holier than thou' attitude helps anything.

The thing about people starting a rumor of a tidal wave to get people to drop supplies they can loot is itself a rumor. People working themselves into a lather over the possibility of a tidal wave is entirely possible. The possibility of a tidal wave was included in the initial reports of the earthquake. That this rumor might propagate and some people panic is possible. People picking up property dropped when people have run away is also possible. If you really needed water and someone drops a jug of it and runs so there is little chance you might get it back to them might be something of a windfall. Would your turn away out of respect for abstract property rights?

But A plus B plus C, barring multiple corroborating witnesses who were positioned to see the entire situation, doesn't amount to making the initial rumor accurate. Has anyone done an investigation. Perhaps interviewing multiple people who would know?

Likewise there are stories of people using burning tires to burn bodies. And rumors of people building roadblocks. But then again where would one safely burn bodies with the only fuel available, tires? In the road makes sense. This is possible. Now burning tires are also a historic way to block roads. So it is not entirely improbable that people just seeking to dispose of bodies and to limit the chances of contagion might be confused with people building a 'roadblock'. Did anyone ask what they were doing and why?

It depends on your assumptions about what people do and are likely to do. We saw the same thing during Katrina when white people taking things from stores were recorded as 'taking what they needed to save their family' while dark skinned people were recorded as 'looting'. There was no effort in either case to interview the people and find out what they were doing and their motivation. A critical lack of investigation and information that allows people to project their hopes or fears onto the situation.