1) I think it's telling that when people discuss how it's said, even when they say they pronounce it with a soft 'g', they'll say "I pronounce it JIF, not GIF", which fully acknowledges that GIF *should* be pronounced differently from JIF, ostensibly with a hard 'g'.
2) Creators are frequently wrong about their own creation. Microsoft didn't create Internet Explorer to just be a way to download Firefox; the creator of the toilet paper roll explicitly said that it rolls towards the wall, not away from. What the creator of the format says is The Way of pronouncing it is meaningless.
3) I've never jiven a jift to my jirlfriend.
4) Gif is an old English word (meaning 'if') that's pronounce 'yif', with a 'y' sound, so everybody's wrong.
5) Even if in the very beginning it was agreed that it was pronounced with a soft G, language evolution continues to be a thing and the spelling, usage, and pronunciation of words WILL inevitably change over time, and getting mad that the majority of people have decided to pronounce it differently from how you intended it to be pronounced is just tilting at windmills.