Would you pronounce it “Grin-drrrrr” because you just want to normalize to a hooked-on-phonics view of pronunciation while using a language that is a crash-merge of proto-Germanic and French with a sprinkling of centuries of colonial cultural appropriation?
“GIF” is like a brand. It’s a spec; a proper noun. As such, it has a clearly intended pronunciation that was unambiguously provided by the creator. That guy is dead now, so he may not notice, but try honoring his intentions for a day.
Everyone who gets dogmatic about “I don’t care what the spec is like” just comes off seeming to me like old Englishmen who quite clearly intentionally mispronounce non-English words (except French, which they relish…).
It used to be that the only folks I knew who pronounced this out of spec were my parents and grandparents (because the didn’t know better and were computer illiterate). Now, somehow, we have rafts of people who have adopted the posture of my parents in the 90s with pride.
I imagine that the next 24 hours will see a lot of these sorts of discussions…