Or to put in a smaller scale and not require adding your own generation, are you stealing from an electricity company's fixed costs if you turn all your applicances off when you go on holiday, or if you have a holiday home which is only occupied 25% of the year? I think the answer is clearly not.

But there's a huge difference between actual zero usage and net-zero usage. That's the whole point.

If you're using a generator (or, as another comment said, just use hardly any electricity) then you're not a burden on the system at all (or barely).

If you're "net zero" because you feed the grid your excess power during the day and take away power during the night, you're using all their infrastructure.

In your example, you don't need the grid, so it makes sense not to pay grid overhead (minus arguments about how we still pay for schools with taxes even if we're not using them).

In the solar example you absolutely need the grid. So net metering down to zero is definitely a subsidy. A subsidy I absolutely agree with, but a subsidy none-the-less.

The vast majority of people are unwilling/unable to think deeply enough about the system to understand it. Thus, the simplified rule of thumb that generating electricity reduces your power bill is needed for them to even understand the general direction of what needs to be done. Perhaps the power utility could include an explainer page at the back of the monthly statement for those with the interest and capacity to understand it. Maybe 2% of people will read and understand it. The other 98% can just be smug about their lowered power bill and blissfully unaware of their part in accelerating the market shift to solar.