This discussion seems to be about modifying a lot more than just sexual orientation. The same technology could supposedly permit people to become a type-A, more conscientious, less-introverted (etc). People could use it to improve their odds of acceptance by elite colleges and employers. They could use it to become more attractive to a loved-one.
To be honest, diversity is more valuable to society than it is to the individuals who contribute that diversity. Right now, society doesn't need to compensate people for being diverse--individuals are stuck with whatever hand they were dealt--so society would face a new pressure if individuals could escape their diversity. This bio-hack could shift social power in a big way.
Before that time comes, society needs to reach agreement about whether to prioritize society or the individual. If we each exist to be part of something larger than ourselves, then let's use the technology to give society even more diversity: develop sexual orientations that never existed before! On the other hand, if we serve society only so far as we have no other choice, then this bio-hack is where society transforms from a heterogeneous body into a homogeneous slime, finally making way for non-humans to take over.
Best Wishes,
Chris