I like PSL. They're probably the best organization in the US right now. They really do not understand the American labor movement though. This is by no means exclusive to them. Basically no organization has a good understanding of the unions. Vaguely posting that the unions should take "bold action" is indicative of how little a grasp they actually have on the labor movement though.
The US labor movement has been dominated by antidemocratic, anticommunist, bureaucratic, class collaborating social-fascists for decades now. They have dug their own graves and now as their heads are being lowered onto the chopping blocks by the executioners of the Trump regime they don't even flail about because they've forgotten how to. Most can't get their members to take action against their employers. They've stopped organizing in right to work states because they can't even get their members to pay dues. They bleed members every year while crooked union officers make off with ten times the salaries of their members. They can only funnel money and maybe some labor-hours into the campaigns of Democrats who betray them time and time again to the repeated surprise of the unions. They will not do anything to resist (except maybe some milquetoast lawsuits) and they will actively oppose their members taking any serious action to fight back.
This is not to say that the American workers cannot or should not be organized into fighting unions, but the vast majority of the existing unions will not lead that struggle or follow the vanguard parties into it. I think it's high time the left in this country recall and recreate the history and success of the CIO instead of hoping the unions figure it out for us.