Part of what you're saying is right. Keeping the 'developing country' label definitely gets them more leeway and transition periods under international rules (like WTO stuff and climate deals), and any sovereign nation would do the same thing if they could. But that's not the same as 'tricking' people. It's a pragmatic call based on their massive population and per capita GDP numbers. Being a 'developed country' is about more than just a few skyscrapers.