Linguistic prescriptivism has nothing to do with it.
English has both pronunciations for "gi" based on origin. Giraffe, giant, ginger, etc from Latin; gift, give, (and presumably others) from Germanic roots.
Using the preferred one is just a matter of politeness.
Also, it's quite ironic to prescribe "linguistic prescriptivism" as wrong.
Insisting on one out of multiple possible pronunciations when most people naturally pick a different one is the definition of linguistic prescriptivism. Politeness doesn't have anything to do with it, people are not required to let individuals dictate how our collective language works.
English has both pronunciations for "gi" based on origin. Giraffe, giant, ginger, etc from Latin; gift, give, (and presumably others) from Germanic roots.
Using the preferred one is just a matter of politeness.
Also, it's quite ironic to prescribe "linguistic prescriptivism" as wrong.