bold of you to assume the existence of an objective right or wrong mapping from characters to sounds
One might argue that "context" is a valid discriminator for that, but your point certainly has validity too. They are just two different arguments. The argument of arrogance in claiming an absolute right from wrong, and the argument that context can make one interpretation more correct because it relates to the meaning and not just the description of something.
There are people whose native languages are in those alphabets.
Quick: How would you pronounce СССР?
Hint: It would be completely wrong, because it's not English.