Extensions not available in private windows

Why are extensions not available in private windows? That makes private windows far less useful.

@Robobo,
Because extensions carry with them data that normally is not carried along into Private windows. It is for – as it’s name implies – privacy reasons.
That said, you can elect to allow specific extensions in private windows by going to Menu --> Extensions --> Manage extensions --> [Extension you want to allow] --> Details --> Allow in private