To add to this, I've been using GIMP on and off for a decade and I've never given any thought to the name. It's all capitalized. I didn't think it was a backronym, I thought it was just an acronym.

I've used this in professional settings (I used to work in academic molecular bio), and I was very evangelical about it. Especially because we're not doing high-level artistic work, we just sometimes need something for processing microscope images or making graphics for scientific publications.

I'd say to any and everyone, "You know, you don't have to pay an annual subscription fee for Photoshop: there's this free, open-source program called GIMP that does most of what you need and you don't have to pay a thing! Want me to install it for you?"

I didn't even think to be embarrassed about the name, and no one ever seemed to care in conversation. As others have said, the bigger impediments are people's attachment to commercial software and interface challenges. This is just an absolutely silly complaint to make.