To push back on this a little: there's definitely historical precedent for anti-regime sentiment bleeding over into anti-populace sentiment. To use your example of WWII, a lot of the anti-Japan sentiment bled over to anti-Japanese sentiment in the US in the form of internment camps.

Of course this was in the 1940s and I like to think that we've become a little bit less racist now. But I've noticed a lot more racist "jokes" on Reddit as anti-China sentiment has risen. Don't get me wrong, we should still criticize China for its many human rights abuses and imperialistic practices as well as their violations of personal freedoms in their citizens etc. etc. but we should also be aware that these criticisms will be used by racists to justify their views and their actions, and call it out when it starts becoming more about the people than the government.