2. Agile is good for managers.
3. Managers run the business and make sure it exists.
4. Programmers need the business in order to have a job.
5. Agile is therefore good for the business,
6. And therefore Agile is good for Programmers, though not personally.
The logic falls apart when you look at different individuals and different companies. For example, if your company is very political then what is good for managers very likely is not good for programmers. If your company focuses on teamwork and has a strong one-for-all;all-for-one culture, then whats good for managers probably is good for programmers.
5. Agile may or may not be good for Programmers.
6. Agile may or may not be good for the business.
Agile is not actually for managers, in that productivity suffers a lot, less software with real value is produced.
But software productivity is notoriously hard to measure, so it is ignored.