PSL is a Marxist org, and thus revolutionary, and isn't trying to win the presidency but delegitimize the electoral system and advertise their platform.

Capitalism cannot be voted out of power—it will take a revolution. The capitalist class will stop at nothing to prevent or overturn reforms by repressing, misdirecting or quelling any form of popular rebellion. Without a complete uprooting of the system that causes all the problems workers and oppressed peoples face, exploitation and oppression will still exist. The capitalist state will continue to rule. Capitalism is a failed system that, in its insatiable appetite for ever greater profits, threatens global ecological destruction on an unprecedented scale, with workers and oppressed people bearing the disproportionate burden of the environmental disaster. More than at any other time, it is the working class that holds the future for humanity. For the people and planet to live, capitalism must go. The Party for Socialism and Liberation is dedicated to building a revolutionary workers’ party in the United States.

The issue with voting reform is that it doesn't really work, anything allowed to pass is weak enough that it won't change anything.