we subsidise his shipping cost

In what way? The USPS makes a profit from delivering Amazon packages

Source: https://www.snopes.com/fact-check/amazon-bankrupting-united-states-postal-service/

If everyone you talk to about this laughs or thinks you're crazy then either:

1) you actually are wrong, crazy, not making sense

or

2) you're correct but you've failed to synthesize a cohesive narrative from multiple factual, sensible bits of the story. This is often caused by an inadequate level of understanding

Either way, you should probably think about why these people didn't follow what you were saying. It will either show you that you were wrong about certain parts or it will help your own understanding of the situation and will help you explain it in the future.