Net metering involves buying and selling kWh. If there are fixed infrastructure costs involved, the companies involved should bill for those separately.

I buy my car from company A and my gasoline from company B with clear prices for A and B.

Why is the scenario where the car company provides my gasoline and then bills for both gasoline and the car in an opaque "single bill" manner, where I can never make out which is which preferable for the consumer?

Net metering is stealing from those who BUY from the providers of the distribution infrastructure, full stop.

Net metering is a subsidy for upper middle class folks who own their houses and want solar panels because it's hip and cool.

The costs get directly passed onto the other consumers. The poor and middle class.

Only in the sense that producing anything as a regulated monopoly is stealing from the consumers of that monopoly good.

People who own solar panels become producers under net-metering. They are just like any other firm in the market. The prices are wonky because they are regulated by law instead of free competition, but the prices of all utilities are wonky because they are regulated by law instead of free competition.