The China-Singapore joint naval exercise is mainly of the kind like passage (communication) exercise and search & rescue operation, just about the lowest form of joint naval exercise.
Now take a look at Singapore's export by country. In 2020, China imported more from Singapore than US did. And Singapore's export to China+HK+Macau was more than US, Japan, S Korea, Australia, UK and EU combined.
Furthermore, Singapore also hosts US warships and Australian Surveillance/submarine chaser P-8, both a threat to China's security. Our forum members will be a bit more understanding if Singapore treats China a bit more fairly.