I still cannot see the issue with Chinaman because: -
- Englishman
- Scotsman
- Welshman
- Dutchman
- Frenchman
I'm sure there are many more and none of them are derogatory so why are the Chinese so precious?
Because in the USA and Canada it got used regularly in the 19th- and early-20th centuries as a derogatory term against the Chinese people who built the railroads and other infrastructure, specifically to suggest they were dishonest and stupid. The Chinese have not forgotten this.
British people, who live somewhere that the insult stopped being used in mainstream conversation before World War I rather than the 1950s, often find this confusing. Especially since other nationalities to which British people attach "-man" don't have the same history or resulting negative connotation.
So its not the Chinese its Americans!