I also think that comparing a structure for relationships to one's sexual orientation is crap. One is just a way to approach having relationships, while the other is who one is attracted to based on the internal interpretations of gender identity/biological sex/gender expression of oneself and the person to whom one is attracted. Much more complex than the question of how many people you feel comfortable having relationships with, IMHO.
There seems to be a new attraction to squeezing "orientation" into this kind of discussion. I expect it is related to the fact that we understand sexual orientation to be somewhat predetermined and that no excuses or explanations are needed to have one orientation vs another. Having the ability to superimpose this certainty onto other aspects of our personality or our life choices would seem to be pretty comforting.
Personally I find this push to be counter productive. I actually find it unfortunate that I don't have the ability (or at least not much ability) to shift within my own sexual orientation spectrum. I think it would be terrific to be able to just switch my sexual orientation depending on where I am and what my current options are. I can't though, because I'm hard-wired to an orientation within a very limited spectrum.
It's a very different discussion with my ability to minimize jealousy, enjoy intimacy with multiple people at the same time, etc. I can have romantic love for one person at a time (and this is the norm for me) but why would I want to cut off the possibility of more with something like calling myself "hard-wired"? There are very few things that a human is truly wired to do; that is, they will turn out that way no matter what obstacles their environment presents. The rest is tendency based on a formula including genetic layout and environmental conditioning over time.
I choose not to limit my options by pigeonholing myself with terms like "hard-wired" or "orientation" when that isn't actually the case.