Firstly, I don't think we should try and cultivate a space where we see poly folk as "victims" and those in here who share their views as non-poly people as "victimizers". We should see the poly orientation / position as strong, rather than weak and victimized.
Second -- OMG! Really? As a bisexual and biamorous (and polyamorous) man who is one of the LGBT folks I find it odd to hear a perspective where LGBTQ folks are seen as perhaps more prone to being unfairly treated than poly folk are. Where I live, one can be out as apparently "gay," which is how most folks probably imagine me (since I have a male partner) ... without much discrimination or foul treatment. But I've experienced a LOT of maltreatment (and lack of acceptance) as an out poly guy. Polyamory, in my experience, is the less socially accepted way of being. In fact, my polyamory may have been a major factor in my recent ... well, never mind.
This gets into interesting nuances. Discrimination against LGBT people has historically been pretty intense AND highly "institutionalized" -- having resonances with institutionalized racism, for example. Or sexism, for example.
The institutionalization of monogamism (as it could be called) ... or polyphobia (as some may like to call it) is far less widely recognized or understood in our society today. And, for this and other reasons, we poly folk should remain open to hearing from people who "just don't get it" about polyamory. After all, it is we who are (and must) representing this as a valid alternative to monogamy -- which our culture (wrongly) imagines as essential to healthy "romantic" love relationships.
It used to be that heterosexuality was seen as essential to healthy "romantic" love relationships, and the non-hets had to make their case to those who thought otherwise. They succeeded in doing so -- because no case was necessary to begin with, nor any defense of this way of loving. And I think society will eventually realize that the same is true of the ethical non-monogamists. So it's not like I think any of these ways of loving needs defending. What is needed is for us not to be so defensive, and to be open and honest about our love.
I've personally experienced and witnessed discrimination for both. I'd say poly people have it "better" based on the fact that I've never seen or heard of someone being physically attacked for being poly (in the West, at least), whereas I've known of people who were killed for being gay. Funnily enough, my male gay friends don't tend to get much harassment and discrimination any more. Not the same for my female friends in same-sex relationships. Maybe that's more about sexism than anything else. Men are still offended by women who are sexually unavailable to them.
I don't think IP is a person who "doesn't get" polyamory. She has been exposed to it and has decided that polyamory (other than solo poly) is an unethical relationship structure as it always involves objectification, coercion and/or couple privilege.
I'm all for educating people about polyamory being a valid relationship structure, but I'm also mindful of protecting a "safe space" for people who are in a minority. That's not to say poly people are victims, and non-poly people aggressors, but broadly tarring all non-solo poly relationships as "unethical" does impede on the "safeness" of this space for a poly person. In my opinion, anyway.