"1/3 of this group might be queer so the whole group is queer" is not a convincing argument
Yes, romantic orientation is an orientation. Polyamory is not about who you feel romantic attraction towards. Therefore it is not a romantic orientation.
This is called the split attraction model. Romantic orientation defines who you feel attracted to (same, different, both, neither ... gender) romantically. Sexual orientation defines who you feel attracted to sexually. An ace person may be heteroromantic like me or they may not be. Whether they are polyamorous has nothing to do with it, see point 1 again.
I am not sure what your point here is. I think a lot of people would like to be able to explore crushes outside of their mono relationships. They don't want to be poly for various reasons, for example jealousy. Being generally less jealous is not an orientation. Then you go in with saying that "normal" people don't understand poly, just like they don't understand being gay. This is true but an extremely vague thing these communities have in common. You could argue that being a teenager is queer on the basis of that.
4.Yes to the first part.
Additionally, poly by orientation people often feel profound discomfort
in monogamous relationships, even when they're not experiencing a
desire for specific people. This seems to be similar to the experience
of gay people in heterosexual relationships (although I can't personally
attest to that).
This actually seems rather offensive to me. No, wanting to be poly is not the same thing as commitment issues, but it is also not the same thing as living a lie. The fact that you would say something like that makes me think that I would feel unsafe with you in queer safe spaces.
Also: why is the only thing that can explain a difference in people an orientation?
Ambiamory is something completely different. It means you can be happy in either relationship style. Lots of people choose poly as their lifestyle because they feel it is the only way they can have happy fulfilling relationships.
If poly is a lifestyle, then why do so many people suck at it
Ok, I hope you are just trolling because what even is this argument???
Also please read my post. I never said being poly can not be an innate characteristic of you. I just said it does not make you queer. "Having a characteristic" is just not the same thing as "being queer".
I'd guess maybe 5% - and that's about the proportion you'd expect if it were a minority orientation.
And what does this mean???
I don't know if you are queer or not, but I think you are lacking a lot of respect for other queer people's experiences. If you ever participate in the queer community, be that as an LGBT+ identity, as an ally, or as polyoriented, please be more respectful and learn about the community.