I think it’s missing the point to say it’s alt-left. In the Uk side of things it was always true r uk was left and r ukpolitics was right, and then there was a fascinating shift in various ways during election times. But either way the core of the issue was just that whatever the prevailing view is drives out disagreements.

Twitter is bad because bubbles form and then they collide causing fights. Reddit solves this by making the bubbles much stronger and ensuring they never collide.