Unable to connect to localhost with mysql utilities
OK, so my suspicions were correct.
The python scripts of mysql utilies use the default "my_print_defaults" utility to get the credentials from a login path.
But the my_print_defaults call returns the password as a bunch of stars, unless you call it with -s...
So I modified the python script mysql/utilities/common/my_print_defaults.py to call the my_print_defaults executable with -s to get the password too. And now it works.