Is it true that people with chronic bronchitis shouldn't breathe 100% oxygen?

Depends... Oxygen should be thought of as a drug and like any drug, there is associated toxicity with using too much for too long. If you breathe 100 percent oxygen for a long period of time, it will actually cause more lung damage. So, no one should breathe that much oxygen unless absolutely necessary and the doctor will decrease it asap. Only when a doctor prescribes it, usually in a hospital setting.
No. Chronic use of 100% oxygen has its downsides. Oxygen in that concentration should be considered a medication in itself, and thus has its set of side effect. The lung when exposed to this level of o2 will exhibit ultimately some of these events given long term exposure.