Not quite a strawman. It was a rhetorical question in an attempt to make people think about how they would respond to the costs and benefits of voluntary work reduction if only they did it and not other peers.
Also, I have seen this line of argumentation. In a thread less than a week ago, somebody said how he found it unfair that I or others might work 60+ hours and he only work 40 and that pay scales should and job promotion abilities should be equal so he didn't have to give up his life to compete against those of use that had a different set of priorities (my terminology -- his was a little less forgiving). People choosing 32 hours a week would be upset to get passed up by those choosing 48+ hours. It's natural.
This reminds me of the old line about peacocks. In every way other than sexual attraction, those enormous and garish tail feathers are detrimental to survival (energy, concealment, agility...). If every peacock agreed to simply scale down their tails, so that the pecking order remained unchanged, the results would benefit everyone.
That's Prisoner's Dilemma [1]. Similar to ban on advertising of cigarettes is said to be beneficial to Tobacco companies. I couldn't find definite quantitative research on this claim. On Wikipedia in economics section [2] this claim has [citation needed] tags assigned to it.
Working time regulations is about preventing companies from using their excessive bargaining power on a tense job market in order to get the most desperate workers accept anything. You can be against it (I'm not), but it's another topic from part-timers vs full-timers.
Regarding wages, it's normal that you make more (ceteris paribus) if you work more. As for promotions, I guess it depends on the kind of role involved; many managerial roles are known for requiring pretty long hours, so this might not be compatible with 32-hour week for a start. But you should be able to move up from, say, junior to senior dev if you got the skills, whatever your working hours. Everything is not possible obviously, but when it is, mere working hours is a pretty lacking metric for merits and promotion--as the article points out.
Well, yes, that's how we got the Working Time Directive and the 40-hour work week. He's right in that economic fortunes are lumped together. Imagine a guy on a motorbike chained to a guy on foot: the biker complains about his speed being restricted, but speeding up is going to be very bad for the health of the pedestrian.
Also, I have seen this line of argumentation. In a thread less than a week ago, somebody said how he found it unfair that I or others might work 60+ hours and he only work 40 and that pay scales should and job promotion abilities should be equal so he didn't have to give up his life to compete against those of use that had a different set of priorities (my terminology -- his was a little less forgiving). People choosing 32 hours a week would be upset to get passed up by those choosing 48+ hours. It's natural.