So sorry this happened, Luckygirl! It's clear that these 3 ladies wanted to go in a different direction from you and, perhaps, J, and that you, in fact, would have preferred for things to go in a different direction than they wanted. It's possible they knew their approach "didn't sit well with" you, but didn't know what to do about it.
Yes, they should have told you and J that they wanted to focus on a poncy approach and, therefore, needed to let you 2 go. But perhaps they were afraid that would hurt your feelings. Or they're just cowards and were afraid you and J would object and they didn't know how to deal with it. Most likely, they thought they were making it easier on everyone by lying. Obviously, to the contrary, they made it harder. But I doubt they thought that would be the result and don't think they intended to be cruel.
Imo, it's great that you spoke up and showed your support for J - IF they knew she was upset by what happened. If they didn't know, then you may have overstepped and spilled her private concerns, etc. I hope it's the former.
Perhaps you and J can start your own poetry club, as someone else suggested - maybe call it "Not a Poncy Poetry Group."
And yes, GNHQ, a poetry group here would be great!