"Manager imposes it on you" just means you work in a team rather than alone. You can pick whatever you like for side projects, of course you're going to use whatever your team uses otherwise.

More generally, when it's not well suited for the problem to be solved. Eager coworkers anticipating Google level traffic may want to write the system in Go and multiple microservices when a simple FastAPI server would do.

Only a problem when a manager imposes it on you for a program where it doesn't fit well.

Plenty of software engineers don't know any better themselves