Well, tbh, I don't totally understand all forms of polyamoury but I'm not against it. As long as no one makes me feel guilty about being mono, then all is fine. I don't see a reason to be against people loving each other. I'd like it if it more things became no big deal, nothing to talk about. Sometimes I feel like social norms are chocking.
I think I understand closed polyamoury better than open type relationships... I guess it's because I value fierce loyalty and commitment, rather than lose and fleeting relationships. I also prefer to feel some level of security and safety.
With my current relationship, poly is out of question. I don't even want to be with someone else anyway (tbh I haven't even found anyone else to be attracted to). We went through a lot and most people would have found it too hard, it was all worth it. I think it made our relationship really solid. I want us to be that couple that grows old together and still love each other after that many years.
But if I was single, and say, had two friends and we all fell in love then decided on a closed relationship with all three of us, then that makes sense to me. I don't have an issue understanding this sort of scenario.
Like I said, it's open ones that I have difficulty relating to. I also don't understand feeling attraction to many people. I can count on one hand the amount of people I feel attracted to and on one finger the amount I felt romantic love for.