It's immaterial what argument the Jif people put forth. It's even less important what Steve Wilhite has to say - also his file format sucks, and I'm glad that between PNG and WEBM that it is obsolete.
What matters is common usage - which is why we
literally have two opposing meanings for the same word which literally makes we want to flay small children.
And you Jif people have lost every poll ever that asked for people's preferred pronunciation, and in overwhelming numbers.
http://www.independent.co.uk/voices/iv-drip/poll-how-do-you-say-gif-8626806.html
http://articles.latimes.com/2012/jun/15/business/la-fi-tn-gif-jiff-25th-birthday-20120615
http://digixav.com/2012/03/11/gif/
http://stancarey.wordpress.com/2012/12/12/how-do-you-pronounce-gif-does-it-matter/
http://forum.bodybuilding.com/showthread.php?t=154446111
http://www.npr.org/blogs/thetwo-way/2013/05/22/186031226/gif-talk-do-you-say-it-with-a-g-or-j
http://arstechnica.com/civis/viewtopic.php?f=23&t=1234495
Common usage doesn't favor you - so, sorry, you lose.
This is besides the fact that there's literally another file format called JIF -
JPEG Interchange Format.
I think the only reason anyone would want to make a point of going against common usage only to create a homophone with another file format is because they are
literally psychopaths. Go eat some fucking peanut butter or something -- unless you write for Slate there is nothing to be gained by being so stupidly contrarian.