Well look, I appreciate the point that there are limited jobs and a lot of qualified people and that the market forces the wages down.
But there is a bigger context here. One is that the market pays him for 225 hours, then expects him to work 280 hours to do the core of the job, and if he wants to do his job properly he'd need to push it up even further to 300. If you want employees to appreciate the cold facts that the market doesn't value them, you should appreciate that employers accept the cold fact that they can't expect an employee to put in 30% more hours completely unpaid. That's not reasonable.
Now you could argue about that for SMEs. Your local cornerstore can't afford to give a full contract to one of its employees because it struggles? Alright. But this is a university with a $200m endowment in an industry where revenues have far, far outpaced the CPI and where class sizes have increased, too. The notion that they can't pay a highly qualified individual with 10 years of experience and excellent ratings for the 300 hours to do his job is ridiculous.
Now you can argue that he accepts a crap job and that the market keeps the wages down. That's all fine. We don't award PhDs more money than street cleaners because we respect them more, but because they're harder to get and in demand and therefore more expensive. And if this is no longer the case, I appreciate you can make the case they don't deserve $100k salaries, sure.
But it's not his argument. His argument is that he gets no worker's rights because of loopholes. No pension or unemployment protection, because the way they define his job, even though it's no different from another job title that does get those benefits. His argument is not that $30 an hour for 225 hours in a course is too little money, it's that they hire him for a 300 hour job and pay him only 225 hours. That has nothing to do with 'it's fine because it's what the market says'. That's just screwing with your employees and being able to get away with it because the market allows it. Pay him for the 300 hours that it takes to do the job right and award him the same worker's rights we have all come to expect in a civilized society that is market driven, but enforces some basic principles when the market doesn't naturally award them, like building up a pension or getting protection for when you lose your job. If that means cuts in his hourly wage to what he effectively gets now ($17 USD), that sucks but it's transparent, it's a signal to the 200 students in his classroom that says 'you're paying a shit ton and this is what the current market offers'.
That having been said, I appreciate your point on market forces and it's exactly blog posts like these that can affect them. To limit the amount of supply of new PhDs looking to get into teaching $60k jobs when they don't exist, you need communication like this. If anything let's applaud that.
As for your point on passing along the issue to those weaker than him... he he has no employment protection, combine that with the fact that he his multiple requests have already been denied, I'd say it's quite brave that he goes public with this, for one. But secondly, it's the way in which he least affects his students. i.e. if he, as you asked, decided to simply not show up to class to push his issue, that'd affect his students MUCH more in a way for which they have no real recourse and in a way that can really mess up their entire curriculum due to cascading effects. (e.g. fail a fall course because of issues with a lecturer or personal issues and you can't start your next course in the spring, and you can't redo the fall course in the spring either because it's only given in fall. So you have to wait an entire year before you're on track again. Stuff like this happened to my peers all the time in uni.)
The fact he continues teaching, continues putting in 280 hours for 225 in pay, pay which itself isn't too awesome in the first place let alone discounted against the extra hours, but deny the extra 20 hours to handle extra support while trying to get a conversation going to resolve this after having tried multiple times already, while putting his job and short-term livelihood on the line (in a position where his family is already classified poor and on income assistance) is 'hardly admirable'? I'd say on the contrary, quite admirable.