Telling me not to is what makes English worse.

In your opinion. "Jiggawatt" is not a common English pronunciation outside of back to the future references at this point. People mostly settled on one over the other because it makes sense to pronounce a word a similar way to be more easily understood. It's not always the case, sure, but I think you'll find multiple pronunciations are the exception, not the rule. That's why you can come up with a good handful of such words, but you'll be using words with single pronunciations to talk about them.