GP is saying that if some is criticising the Chinese government, it does not imply that they are being racist towards Chinese people. But these students try to muddy the waters by conflating the two issues.
Not really. When someone is very anti Israel, more often than not, if you dig a little deeper you find an antisemite.
But when people criticize China, they criticize the politics and you almost always find them praising Taiwan and Hong Kong, invalidating the idea that they're racist.
Different people have different motivation: among people who criticize Israel there are people driven by antisemitism. Of course not all critics are antisemitic. The same with China - some can be right (in critics of CCP) for wrong reasons (xenophobia/nationalism). Or one can criticize specific policies for good reasons and be labeled as a racist.