A word of advice: anyone who says any sort of development platform is a joke is a loving moron. There are millions available, none are better than others, and they all have their own strengths and weaknesses.
Using C++ and an engine/library (e.g. OpenGL, SDL) can produce fast, efficient results, but it's relatively difficult to learn and use. A program like Scratch, however, is very easy to use and is good for learning programming concepts, but has super bad performance, portability, and is bad for anything productive in general.
To answer your question, yes, GM would be a good option for your purposes, but it's also good to look around and see what fits you best as a developer and designer. On the other hand, if you like what you're working with and it works fine for you, there's no reason to switch, especially if someone else and their "master race framework" tells you to do so.