I'm not arguing GIMP vs. Photoshop anything. I'm just pointing out that you shouldn't exclude making icons from "high-end graphics projects." What do you think graphic designers do? A lot of graphic designers make logos, UI elements, website graphics, application icons, etc. This stuff isn't Artâ„¢. It's not a metaphor for the human condition. It's a picture of a pencil being used for an edit button. That's what pays. It's just like music; you'll make far more money scoring commercials and writing jingles than you will selling your Concerto in D Minor.
But anyway, odds are if you're serious about graphic design, you should be buying a copy of Photoshop anyway, because yes, it is industry standard, and yes, you're going to be using it for work.
Most people who pirate Photoshop are not graphic designers, and most of those people don't need to be using the "industry standard." They can get by with GIMP. Hell they can get by with Paint.NET. To be perfectly honest, they can probably get by with some of those online image editing apps.