This is the real story here I think: people invented the rule to suit their preferences, but over time we've forgotten the rule's origin and now treat it like a holy truth. (Or worse yet a matter of "grammar"! Run, run - you've made a grammatical mistake!) You are likely to discover this over and over again if you study the background of many rules that (some) writing teachers insist on and that people like Lynn Truss use as an excuse to foam at the mouth.
Here are some of my least-favorite myths, in no particular order:
+ You should never end a sentence with a preposition. (Sheer bullshit: English uses countless phrasal verbs ('throw away') and in many other cases avoiding the final preposition produces stuffy nonsense.)
+ You should never split an infinitive. (A completely made-up rule, based on mistakenly trying to apply Latin rules to a Germanic language.)
+ The word 'hopefully' can only mean 'in a hopeful spirit' and therefore you shouldn't say, "Hopefully, we'll arive before lunch tomorrow." (Sheer bullshit again: 'hopefully' there functions as an adverb modifying the entire clause 'we'll arrive before lunch tomorrow'. The sentence as a whole clearly and obviously means "It is to be hoped that..." or less formally "We hope that..." This use of 'hopefully' is no different than 'fortunately', 'sadly', 'happily' or 'luckily' in countless sentences.)
+ Don't start sentences with 'but' or 'and' or 'however'. (Just goofy.)
+ Never use the passive voice. (Overdoing it at the least: Yes, a lot of beauraucratic and other bad writing uses the passive in excess, but the passive is not per se evil or always wrong.)