The stereotypes surrounding polyamory and the comments under fat queer people's posts making shitty jokes about polyamory
This is fatphobia and polyphobia.
seen from Lithuania
seen from India
seen from China
seen from China

seen from United States
seen from United Kingdom
seen from France
seen from China
seen from France
seen from Malaysia
seen from China
seen from France
seen from United States
seen from Singapore
seen from China
seen from United Kingdom
seen from Brazil
seen from United States
seen from Sweden

seen from France
The stereotypes surrounding polyamory and the comments under fat queer people's posts making shitty jokes about polyamory
This is fatphobia and polyphobia.
"Polyamory isn't queer because it's a lifestyle choice! Lots of polyamorous people choose to be in happy monogamous relationships instead!"
First of all - the idea that polyamory is a lifestyle choice comes from the fact that people don't understand ambiamory. Ambiamorous people are people who can be fulfilled by both monogamy and polyamory.
And just like how a greysexual person might identify as asexual because they fall under the acespec umbrella, an ambiamorous person might identify as polyamorous because they fall under the ethical non-monogamy umbrella.
People who are strictly polyamorous do not ever want monogamy, not in a long-term sense. They will settle for temporary monogamy, but that is not what brings them fulfillment.
Second of all - what marriage rights do polyamorous people have? What relationship rights do polyamorous people have? What adoption and familial rights do polyamorous people have? How many families would actually accept if their child came home and said they had multiple partners?
Have you ever considered that maybe, just maybe, polyamorous people are being forced into monogamy through lack of rights and acceptance?
I'm not sure if im just imagining it but:
The fact that polyamorous relationship terms like metamour aren't even understood or recognized in queer spaces, despite the words being around for years
The fact that people have mocked an online friend of mine for having 3 parents (their mom and dad are married to eachother and have a third partner that they're both dating in a polyamorous relationship)
The fact that polyamorous relationships are scrutinized so much more heavily than monogamous ones, and minor disagreements in them (like arguing over what to eat for dinner or over where to go for dates) are treated as seriously as literal abuse would be in a monogamous relationship
This is mononormativity/polyphobia.
You aren't imagining it. I have experienced it first hand.
Polyamory is widely unincluded, erased, and demonized within queer spaces. Our terms are seen as unnecessary attempts to "fit in" with the community, and our language is viewed as something unimportant to learn because people do not believe polyamory will ever be something bigger and more normalized than it is now.
People treat having more than two parents as something negative, and view it as "your parents having a kink", because they cannot conceptualize that polyamory can be something deeper than simple hookups (and they view sexual promiscuity as a negative trait, which is an additional issue.)
And polyamorous people are constantly encouraged to breakup. Told it "won't work out" and that monogamy is just "less difficult" or "less toxic."