Because the Overton window moving ever rightward gets super depressing sometimes.

When I voted for the first time 22-23 years ago, my core ideological beliefs were slightly to the left of the main center-left party of my multi-party country. Nowadays they're all considered far left bordering on (peacefully) radical.

Especially sucks to be a pacifist in a world that collectively agreed that militarism is great again and an egalitarian in an increasingly racist and otherwise bigoted world.

And that corporations still mostly get away with doing whatever the fuck they want everywhere as long as they keep legally bribing the politicians of the country that more or less dictates what other countries get to do and not do.

Tl;Dr: leftist ≠ democrat and is frequently a depressing and frustrating thing to be in this fucked up world