Why Flash Is a Good Environment for New Game Programmers
Flash is an ideal environment for beginning game creation. Flash makes a lot of the implementation easier, so you can concentrate on the content of your games instead of all the details of memory management, image drawing, and reading the input devices. (Fancier environments make you put a lot of work into such details instead of mastering the craft of game development.)
Most commercial games are written in 2-D, using C++ and graphics engines like DirectX or OpenGL. Those are really great environments, but they aren't necessarily what you need while you're learning the process of game development.
If you want to be a racing champion, you don't just show up in Indianapolis with a helmet. Starting your driving career in a high-performance machine is foolhardy and dangerous. You begin your career by racing go-karts and then advancing through more challenging vehicles. That's why you should start programming with Flash and ActionScript:
C++ is like a Formula 1 car — fast and difficult to handle.
Flash and ActionScript are like a go-kart (albeit a souped-up, Internet-enabled go-kart that outperforms any computing environment NASA had during the moon program).