I honestly can't see why this is "fine"... I understand it's not the security critical bug, but feeding all environment variables into some sort of interpreter...?!?

Ok, bash needs to transfer function definitions to child processes in order to implement something called inherited functions, and I guess you could argue that an environment variable is a reasonable place to store them. But WHY THE HELL does bash have to use the function name as the variable name?!? That's just insane to me...

Any sane programmer would store that shit in an environment variable with a known name (e.g. "BASH_INHERITED_FUNCTIONS"). Why doesn't bash do that?!?