I grew up in Bombay, whose name was changed to Mumbai some time in my childhood. My friends and I still call it Bombay. We use “Mumbai” in more formal contexts, or with people who grew up in a different city.

Similarly, I know of people who say “Calcutta”, “Bangalore”, “Gurgaon”, etc.

The thought of colonialism does not occupy mindshare. It is just the name we grew up using and find it comfortable to continue using it.