I think it's complete non-sense that a person who works hard and has proven themselves repeatedly in the past would need to change their attitude to get promoted. I would definitely take it as an insult and I'd likely be looking for other work. Some people don't want to be promoted, but some do, and if you do, and your company tells you it's not happening, it's time to look. You can probably jump in at the level you want to be, and forget about working your way up at that place that doesn't appreciate you. That person's thinking is way off-base and old-fashioned. Being a good manager means being tolerant, not being a bully. it's give and take. Everyone I know who works for a bully quits and goes to a different job. The only reason I've been at my job as long as I have, is because the people are nice.
Are you male? I notice with women, employers make these types of excuses to keep you down & ensure you're feeling less confident, so you feel trapped. I hate the rat-race.
I'm a guy. The new boss is using the guise of "being more confident" as a buzzword to be a bully. For the first time in a long time, I dread going to work. Just because of this guy, he has a lot of us on edge and we're all pretty fearful of what he is trying to accomplish.
There is a coalition of the willing outside of my department who feel the same way about
him. If any of you have watched The Office, i'm in the Charles Miner series of episodes.