I'm not a fan of Tesla, but... this seems right? A postal service (even a privately-run one) should not be allowed to discriminate when it comes to delivery, outside of hazardous or illegal items.
This doesn't even seem very privately ran.
I would hope for anyone that complains about the USPS and says we should use private companies take things like the private companies just saying 'no' into consideration.
Postal Service shouldn't be allowed to effectively enact or modify government policy! More to the point, Labor Unions shouldn't be using a subverted power of the state to coercively unionize workers against their wishes.