Because it can often mean that they lack dispassionate objectivity. How often have you seen starry-eyed people like this push their pet technology into a proje

Because it can often mean that they lack dispassionate objectivity. How often have you seen starry-eyed people like this push their pet technology into a project just because it was their passion, but without any view as to the wider technical context or business context. They can be a real menace. Not because they aren't technically competent. But because their judgement is poor. Looked at from a distance, they aren't looking at what's best for the company or the project, but what's best for themselves.