While I agree that there are, in general, significant differences in positions on these things, this seems like a bad example to choose: after all, US rail workers went on strike over the safety, long hours, and being expected to work injured or sick, and President Biden signed off on laws making their strikes illegal.
Unfortunately, at least in the English-speaking world, many nominal workers' parties have largely bought into worker-hostile policies under Blair, Starmer, Clinton, Albanese, and so on.
Honestly, I agree with you on this; however, the grandparent didn't say "Democratic or Republican politicians," which is very much the source of the problem you describe. Their wording was "conservatives or the left", which I think it is fair to say includes the people who identify with those political orientations—and I think you'd have a hard time seriously arguing that "the left" in America, to the extent that it even exists, is not strongly in favor of labour unions and worker protections.
I think the grandparent was really referring to extremities at the tips of the two wings - the cargo culting 'democratic socialist' movement the DNC pays lip service to, and the extremes of nationalist'USA first' 'patriots' the RNC pays lip service to and the DNC's coastal media corp friends love to endlessly frightened their viewers about.
Unfortunately, at least in the English-speaking world, many nominal workers' parties have largely bought into worker-hostile policies under Blair, Starmer, Clinton, Albanese, and so on.