It's a lot more reasonable in a dead-end or cul-de-sac, where any car is either going to one of the houses there or got lost, and where no vehicle should be moving at more than walking speed.

The same logic applies to non-dead-ends if only people who live in the neighborhood use them. That's why people don't want "their" neighborhood streets used as cut-throughs.

Then those people should move to dead-end streets. Because again, it isn't "their" street. It's the public's street.

You are correct. It is not "their" street. However, it is not unreasonable for people to expect that neighborhood streets not be flooded with traffic beyond what they were designed to handle nor put to purposes for which they were not designed.

It is a public street that was designed to service the neighborhood and the traffic traveling to the neighborhood. It is not a highway.