Polyamory doesn't liberate; monogamy doesn't protect

I generally agree with what you are saying, but you need to add "and not fighting" to "long term committed parents who are always there." Not fighting is so important that sometimes the parents need to split up so they can stop fighting. They can still be committed parents who are always there for the kids while no longer in a relationship with each other and the kids will do well.

I really really wish someone had told me that a long time ago, and while I'm wishing I wish someone would have told my children's grandparents that an even longer time ago.

I liked this, but I feel like it glosses over a significant dynamic that discolors both sides of the mono/poly split, which is "people not living the life they want".

Not that it's literally "coercive" -- they're not being forced to be in that relationship in any real sense. But the dynamic I often observe (well, infer from observations) is that a person would really like to monogamous or polyamorous (or a different kind of polyamorous---just, they want to be in a different status) but feels they aren't allowed to assert what they want from their partner(s), and a result is being somewhat "degraded" by the status of their relationship. They may even believe they are happy with everything, because it's the best thing they can feel they can get, but often (I suspect) there's an arrangement they would be much happier with, if they could bring themselves to insist on it.

After all a person ought to aspire to be physically and emotionally secure enough to assert what they need from their partners, even if that risks the partner leaving them, and they ought to be able to find partnerships in which their partner respects them enough to compromise or negotiate if it is something they truly need.

But I suspect a lot of people aren't there, and being mono/poly is often a "workaround": if you don't believe you can fully assert the relationship you want, sometimes you can get half of it by becoming monogamous/polyamorous instead even if it's not truly your preference. And maybe that lets you avoid the issue, sometimes for years. But it's never as as good as being able to get what you truly want.

(Occasionally I mention this vibe to people and they react negatively---"who are you to question other people's decisions?", they say. And at one level they're right, because yes, everyone out there is pretty much day-to-day making the best decision they can see to make for themselves, so if they're coping with their world by being in a certain kind of relationship, it's not really our place to doubt them.

But on the other hand, you can sense when someone is not living their best life, whether it be living the relationship they want or having the job / friends / beliefs / sexuality / gender that they want. You can't be sure, but these things do show a bit through cracks in the way that people talk and act. So I think it's fair to observe this phenomenon and speculate about it, so long as you never push anyone to "admit" to it, or to change before they're ready.)

Disgust is an interesting response to this experience.

I encourage you to reframe your thoughts in "is they consenting adults?" and then "is this hurting anyone?" if the answers are "yes they're adults and they're not hurting anyone", I encourage you to mind your own business :)

Gay people aren't "shoving things in your face" when they kiss, or can be seen holding hands, or have representation in a book or movies because the author wanted to represent themselves in the media any more than straight people are "shoving things in your face" when they kiss, or can be seen holding hands, etc. Equally, non-monogamous people aren't shoving anything in your face by existing in a way that makes them happy and affirmed. Disgust over other people's choices and lives and the subsequent attempt to squelch that is very anti-liberty.

That's probably up to whatever the couple thinks, and has no universally correct answer

It just seems absurd to suggest that a monogamous couple who has one single threesome, one time, and then never again, is now "non-monogamous" forever

> but children need the stability of long term committed parents

You can have long-term, committed throuples, just fine.