Is it that if they're just blocking the vehicles that are subsidized? Let's see what these EVs sell for without the Chinese government paying half the production costs.

Everything you said is true, except you are missing the context that this is for-profit US car companies not wanting to compete against state-owned car manufacturers who get all of their money from China and can take huge losses in order to outsell for-profit, private entities.

There can be no market that is both "free" and "fair"

For a market to be fair there needs to be constraints in the right places

In this case the lack of constraints sufficiently restricting the ability for companies to pressure (read as bribe) politicians to push for a lack of subsides for specific sectors of an industry

The key word there is "company." Chinese car manufacturers are not companies, they are the state-owned entities.

These vehicles would also be eligible for those subsidies if they meet the criteria of being assembled from mostly North American parts. You're comparing subsidies available for every company meeting certain criteria (even these Chinese companies) versus subsidies available only to those companies owned by the Chinese government.