I agree that language is fluid. However, when it comes to names, I think people should have enough respect to pronounce things how the creator (or owner, depending on the situation) of the name says it should be pronounced. Too often people will mispronounce someone's name as a sign of intentional disrespect (see Kamala Harris for a fairly recent prominent example) and I cannot get behind that. You see a similar disrespect in the hard-soft discourse around the pronunciation of GIF. A lot of people use the hard g and mock the creator for thinking that soft g should ever have been right.
Naming is probably one of the few language areas that I think should be prescriptive, even while language at large is descriptive.
I don’t think technical standards merit the same level of “deference to the creator” as personal names. People are wrong about standards they created all the time (ask me what I think about John Gruber’s “stewardship” of Markdown) and should be corrected, a standard is meant for all. Obviously the pronunciation of an acronym isn’t anywhere near as important as technical details, but I think the principle holds.
A child is presumably a sentient being, and at some point in their life should gain control of their name. In fact, they do, to some large degree. There are means to change one's legal name, or one can diverge from their legal name and professionally/publicly use a completely different name.
A file format is not a sentient being. The creator's intent matters much more. If GIF had sentience and could voice a desire one way or the other, the whole discussion would be moot as it would clearly be disrespectful to intentionally mispronounce the name.
If the creator insists on a weird pronunciation, because of an inside joke most won't ever get, then I feel no responsibility in humoring them.
The G in gif is for graphics. Not 'giraffics'. And most people in the world have no idea what Jif even is, much less a particular catchphrase from an old ad campaign that barely even connects.
Naming is probably one of the few language areas that I think should be prescriptive, even while language at large is descriptive.