Dann muss man schon auch als solcher tätig sein, sonst nicht.

Software yes, actual no

But the question was why

In Germany the title engineer is protected by law but with a computer science degree you may call yourself an engineer.

I did not try Threads so I do not know. The post suggests that your user handle appears as a suggestion of a profile to follow for other people even if you never signed up.

Being able to use the same credentials for logging in is something else than creating a public profile for users that never signed up for the service.

You guys wear trousers?