No, frangible and fragile are not synonyms.
Do you see the word "fragile" on a box of bullet? No!
But the word "frangible" is used in bullet literature...you can drop a bullet and it doesn't break...like an egg does.
Literacy is important....especially when folks are teaching others to apply technical terms in a technical way.
Or should we all dumb-down together?
yeah, every profession has its esoteric language. In the Navy, you have to call the "potty" the "head" but it's still a potty.
No we don't have to dumb down together, I'll be happy to stay down here by myself!