The PRC is trying to crush any and all competition. This isn’t them being ecologically friendly or magnanimous in any way. The entire point of this is so they can do the best they can to corner the market, which is easier when the government you operate under just hands you money so you can immediately recoup substantial fraction of your balance sheet liabilities. They are doing this because they want to control the EV market, which will give the PRC a substantial amount of geopolitical power (case in point: look at Taiwan with their chip foundries). And, of course, Party officials and the corporate leadership of their car companies stand to make a fair bit of dosh too.
More broadly, I don’t like when any country does this, including the US. The primary reason I’m singling the PRC out here is because that’s the topic of the post.