That's only the case if you look at it from the supplier's perspective: "We're giving you so much! So you should give us every last penny you can afford," or (more hyperbolically) "It'd be a shame if something happened to your business here in our territory. Want insurance?" The research has already been paid for by its initial funding. Why should we have to pay an intermediary to access it?
In other words, the question is not how much access to all the world's scientific knowledge is worth, but whether it's acceptable for an entity that had no hand in creating that knowledge to control access to it.
I'm not arguing that this price is correct, just that the OP was over the top. (In fact, I'm a strong believer that the correct economic equilibrium is for the grants to pay for the publication process, with all publications being available free of charge.) If Six Flags amusement park takes advantage of their local-monopoly by charging $3 for a Coke on a hot day, this is an inefficient situation but it isn't appalling. A bit of perspective!
On the other hand, if the university was charging the students $10/hour to access journals they needed to read to graduate, that might indeed be appalling. But, as I originally emphasized, students don't have it that bad!
Ok, I see your point. Still, I can't help but feel like your original counterargument (and the position of the journals) is similar to the argument that getting hit in the head every day with a spoon is better than getting hit every day with a club. It's a tactic used by the copyright industry, for example. They'll say, "Don't like being sued for $1.92mil? How about we shut off your Internet access instead?" Internet disconnection seems a lot less bad than being sued into oblivion, but it's not the only other option (e.g. copyright owners could leave TV shows on Hulu and Netflix instead of teasing with one season, then taking them down).
So to sum up, I'm just trying to avoid and counteract the use of some rhetorical techniques I find off-putting, such as
In other words, the question is not how much access to all the world's scientific knowledge is worth, but whether it's acceptable for an entity that had no hand in creating that knowledge to control access to it.