I have always wondered about handedness in weapons practice as well.
I have a few responses.
i.) As far as this being a stupid irritating question, maybe it is. For me it's non-trivial. Often in martial arts it is difficult to tell which things are completely practical, and which things are cultural. It is difficult sometimes to understand the motivation behind things, to really understand the contaxt.
Yes it's true, you could say that one should figure it out on one's own, but books can't always be trusted. Also for someone with as little sword combat experience as myself, figuring out the answer through experimentation is not likely to give a correct answer to the question. It's good to be able to ask questions of our seniors, and have the security of being answered honestly and with respect.
I myself get irritated when I must answer questions that seem obvious or tedious, but I know that this can really hurt people who are trying to learn.
ii.) People may not like this response. I admit that I may be misunderstanding.
I have been to aikido seminars, where we were told that everyone's aikido is different to some extent. Maybe there is room to explore this with weapons as we do with empty handed techniques.
iii. I am left handed and have at many times felt quite oppressed in small ways. However, I don't really feel this way when practicing kata with bokken. For one, the kata's are no longer the katas when the people doing them are opposite handed. Secondly, lefties are used to needing to be a bit ambi-dextreous, where right handers are not. It seems safer, at least at the lower skill levels (where I live) to pick an orientation and go with it.
iv.) I am getting in over my head here, but something to think about is the book of five rings (Musashi Miyamoto). He said that it is wrong to fetishize, or to have irrational inclinations towards a longer or shorter swords. He seemed to have a sense of being open in general to whatever is most practical and appropriate in a given situation. In some ways he seemed to believe that too much rigidity will make one lose the point.
well sorry for the long winded response. I hope that nobody thinks that I am trying yo argue or bait people. I just thought that some of these ideas may blend well with those already expressed. (Even if they're wrong, hopefull they'll make the correct ideas stand out more).