In language usage, the specialists distinguish between prescriptive and descriptive use. To simplify, the first is what you should say and the second is what many people actually say. When the descriptive becomes the norm over time, it becomes accepted.
That's fine and dandy. For your own language, not for other languages. You can say EYE-ther or EE-ther. Either (which I pronounce EE-ther) is OK. But you do not usually know how to pronounce a foreign language. No one expects you to pronounce "spaghetti" and "maccheroni" exactly like an Italian, but no one expects you to say "spajetti" or "matcheronie" either (EE-ther).
If you can say "Chianti" with the k- sound, you can do the same for "bruschetta."
Addendum: I have since found that the Oxford English Dictionary (the standard for our language) does know how to pronounce it, bless its little heart. Three cheers for the Brits: they may not know how to cook, but at least they try to refer to others' cooking correctly.