This is why so much of the left has given up on labour.
The structure of the party is set up to look democratic. But allow leadership to completely silence members they disagree with.
No matter your opinions on Corbyn. And he is far from perfect. He did try to move the party closer to a membership directed one.
And the post Corbyn leadership has worked bloody hard to remove those changes. The PLP and party control knows full well the membership is further left then they are. And considers it their right to take there fees as the only viable alternative to Tories. While working to ignore their views.
A different party is now the only option. The only question is how we pull the left of centre voters together enough. To support one party and beat FPTP. At least long enough to remove it.