If you've read the article as you claim, please quote where she says anything that shows she is anything but a leftist.

The point she is making is about not falling into the trap of tribalism. I am very much to the left (pro UBI and nationalization of key industries), but I am regularly disheartened by the primitive hostility and immediate irrational dismissal of people and ideas on the right (or even 'not far enough on the left'). That (we think) they're wrong doesn't justify treating them like shit and doesn't improve the discourse.