In and of itself, teaching in China isn’t necessarily a bad thing. It can be a way to experience a truly different culture. Ditto for honeymooning there; I’ve been to China and there are some truly incredible experiences to be had there.
Walz also wasn’t necessarily wrong to say that China could accomplish anything if it had the right leadership.
The difference comes in the attitudes, actions, and meanings around those actions. If he and his wife then went on to praise the Communist government even after returning (criticizing Communism or government leaders while you’re there is not particularly safe), and their idea of “right leadership” is an even more hard-line communist leader (which he likely does), then yes, he deserves all the condemnation.
The Chinese citizens aren’t the enemy; their government is.
Walz loves Communism—but he thinks the Chinese Commies did it wrong and he could do it better.
“It can be a way to experience a truly different culture.”
You can get that experience everyday in big democrat cities...usually not a pleasant one though.