Well, it all depends on where you get your electricity. The vehicle is purely electrically driven. It does have a petrol driven generator to top up the battery, but the engine is not involved in driving the wheels, so could easily be described as all-electric as you can rip out the engine and the car still drives.
No, a hybrid is not an "all-electric car." The Fisker Karma is a series hybrid, not an "all-electric car." There is a huge difference between an "all-electric car" and a hybrid.
Being able to easily describe something one way does not necessarily make the description accurate.
The tesla has a large amount of batteries, charged from an external generator.
An "all-electric car" such as Tesla's Roadster, Model S, or Model X can obtain its electrical energy from any number of sources. That's one of the major selling points for "all-electric cars." Sure, The Fisker Karma is a plug-in hybrid, but it has a much smaller battery capacity than a comparable "all-electric car." Its ability to make full use of plug-in power is limited compared to an "all-electric car."
In summary, a hybrid and an "all-electric car" are not the same thing. They target different segments of the vehicle market.