If you think they were commenting on physical labor your reading comprehension is poor. The example job could have been a “non physical” job, say the hallway CCTV monitor, and made the same point.

Their point is that labor they consider low impact or menial doesn’t drive returns, and therefore shouldn’t share in the returns. You’re right that the labor being physical is incidental, really they’re just classist/elitist and any job they consider beneath them would fit this model, while others wouldn’t. There’s a reason they chose a cleaner (and a woman!) instead of a product manager or CPA, though the quality is also unlikely to differ between spaceX and Walmart there.

Speaking of reading comprehension, they didn’t address the core argument of the person they were responding to, which is that labor that falls “beneath the fold” of this class line is not able to negotiate aggressively due to the inelastic costs of food, shelter, and basic necessities. It doesn’t matter how “high impact” you are, if you’re negotiating and need to eat you’ll accept any amount that lets you eat.

In fact, having impact or driving revenue is never the most important factor to reaping the rewards. Anyone who’s worked for a few years with their eyes open should reach this conclusion unless they have some strong motivation not to.