You pay for supplying energy. Isn't that a good deal?
Then... don't supply? What's the problem?
It's the same for every producer. Negative priced hours are a reality everywhere with hourly (or 15-minute, or whatever) pricing based on auctioning on free market. We have negative priced hours here, and that actually means that the nuclear operator has to pay for dumping their unwanted energy into the grid, and consumers get paid by using this unwanted energy.
Every market in existence works the same way: people pay to get food when they are hungry, but if you go and force food down the throats of people not interested in eating your food, police gets involved. Why would electrical energy be any different? The grid collapses if you forcefully push more energy than is consumed, there needs to be a way to turn off excess production when unwanted.
And people do not act upon hopeful wishes. Money, aka giving negative cost (or actual fine) is the easiest way to make people comply. Unsurprisingly, some % of people are stupid enough they don't understand this at all and continue to push their product onto others and then complain about a "tax", which is not a tax, and has nothing to do with taxes whatsoever.
You can hit your head on the wall and wonder how it hurts, but you can also choose not to export energy when the grid does not need it:
* By increasing self-consumption (by using simple low-cost timers, or real automation system),
* and, lacking a way to further self-consume, just turn the damn inverter off;
every new solar inverter (I think at least in EU it's now by law) manufactured within last x years already have simple digital inputs that can be used to limit production - e.g. again with a simple timer if you don't have a real automation system.
Most of the electricity production methods never fully coincide with the use. For example, nuclear is nearly constant output + random and planned total outages. Usage patterns are far from constant, and by Murphy's law, outages coincide with worst case usage. Wind power produces power when it's windy, and solar power when the Sun's shining. And
some % of that, on annual scale, is not going to coincide with consumption. Deal with it. Take it into account when building a system. Sheesh.