@Hairy Scot: don't confuse me for their defender. I'm just stating the fact... I'm not in the position to judge the evolution for the direction its taking, either.

Let's get back to your original question: why does sports media persist in the use of the phrase “hone in” instead of “home in”?

Because they can. Because nobody cared/cares about this, and something they may have started as a word-joke is so widely spread, that it's accepted as the norm. The language is alive, and that's just another example of its slow but sure evolution.

well...

If you consider a phenomenon known since 1965 to be "traditional", traditionally, a missile hones in on a target.

http://www.merriam-webster.com/dictionary/hone%20in

I thought the rule was rather about the language being American English vs. British English...

well, I believe the reasons behind this phenomenon (which I have been observing at least for 5 years now) to be, primarily, laziness, ignorance, and mispronunciation. Universal availability of the Internet, with English being the primary language--but still, second language for I think the majority of its users--of all informal Internet communications, certainly is a factor that increased the commonness of this error. If the communication you are making is a) quick, b) insignificant, and c) performed with less than perfect command of the language, you start making this kind of mistakes. your welcome ;-)