They’re literally producing more panels than the market can handle.
They are creating panels that go unsold which is driving the price down.
Price going down is a good short term thing HOWEVER they’re also destroying any competition (which generally is considered bad in basically any economic system) by doing so. The assertion is that china is deliberately driving competition out of business so they can corner the market.
Prices going down is very very good.
Prices being artificially held down so a market can be cornered is not good even if it had that initial short term positive result.
This isn’t about economies this is about having a robust supply chain which is important for everyone, if we have to rely on china then we are beholden to china. It is this last point that has China acting the way they do.