It's reductive to point out that the US has democracy and China does not? These are fundamental differences between the two. The argument the OP posted is like saying that Iran executes gays and apostates because of where power sits in their government and not because that power (regardless of how centralized it is) is wielded by religious extremists
Besides the fact that democracy and dictatorship having become meaningless keywords for good and evil, the difference in governance between US and China is a lot more complicated that democracy and dictatorship. It's an incredibly simplistic way to compare the two countries.