If someone presents work that a person is impressed with, it shouldn't matter to that person if the software they used is perceived as inferior.

Also, I think it's more likely that a person simply hasn't heard of GIMP, rather than having heard that it has a reputation for anything.

that the lanyard or boondoggle string is named gimp in some places

I had no clue, I've never heard of that. What region is this in?

and no one around here knows that it is a slur in other places.

It's not just a slur though. That's what I understood it as for a long time, but then I found out that it's also a thing in the kink/bondage community. Apparently it's what they call a dude wearing leather straps on his torso and a leather face mask that covers his eyes and sometimes mouth. I think it's a submissive role? I don't know much about it though.

But yeah so I can see how saying that in a professional setting could be off-putting to some colleagues...