An echo chamber is something a thread becomes. Not something you attribute to a single poster. Analogically that’s like calling one person a crowd.
In reality there is one poster in agreement and you.
There’s gaslighting and then there’s whatever reality you’re trying to create out of thin air here.
I don’t know who ultimately is right about the discussion at hand, but what I can say is that resorting to accusing the OP of living in an echo chamber, or of fishing for sympathy, then your argument cannot be that sound.
It feels like you’re arguing about something adjacent to that issue and trying to make OP have that battle with you instead.
I know you know what an echo chamber is and you surely know this isn’t it. There are four of us in this thread and I don’t count.