I disagree with both of these as absolutes. My manager's job is to advocate for work for his team, to make sure our work is aligned with the company's strategic and tactical goals, and to keep the individual contributors' morale as high as possible. The latter is looking after the team, of course, but realistically sometimes the needs of the company and the desires of ICs on the team diverge. In that case a manager's job is to transition those members who aren't in alignment off the team, preferably to another in the company if their talent merits but out of the company is a good solution also.